The craving to score goals, which has burned inside Jermain Defoe since he was a kid kicking a ball around the streets of east London telling himself to "practise, practise, practise", shows no sign of abating. There is something of that determined child still in him today, and it will stare him straight in the face when the 30-year-old wakes up on Saturday morning, walks into the gym he has at home, and takes a look in the mirror. There, right in front of him, is a list of the top 10 goalscorers in Tottenham Hotspur's history. He wrote it himself, starting with Jimmy Greaves's 266 at the top. He stuck it to his mirror so he can get a good, regular reminder of it. He gleefully amends the names and numbers where appropriate as his own goal collection grows.

At the beginning of November, after plundering a hat-trick against NK Maribor in the Europa League, Defoe went home and grabbed a pen. Those goals had taken him up a position on the goalscoring charts, ahead of Teddy Sheringham, on 128. "I went in there and crossed out Teddy's name and put mine in," he says, chuckling at what some might perceive as a slightly embarrassing confession. But at the same time, there is an earnest side to it all. "It's quite sad really ... But I think it helps my focus," he explains. "I know it's about the team and this is a personal thing, but at the end of the day if I am scoring goals it is helping the team. Having that there, when I get up in the morning I go in and have a look at it and that's a good feeling."

Defoe is thoroughly enjoying his football at the moment. He has already exceeded one of his targets – he aims for 10 goals before Christmas as a marker, but has 12 – and is grateful for the absolute faith of Tottenham's new coach, André Villas-Boas. Defoe may be seen as one of 'Arry's boys but he could hardly sound more positive about André's ways. The jury may be out for some but Defoe speaks with enough genuine fondness and enthusiasm to suggest that the players are won over. It is the little things that seem to be making a big difference.

"Away from football, as a person, he is a top guy, a really nice guy. After every session he will come into the changing room or treatment room and go to every player to see if you are OK. 'How do you feel? How's your legs?' General chit chat. He will do it with every player, every day," he explains. "Even when I was away with England he will send me a message sometimes – 'Good luck. How's the game?' Stuff like that. When you have got a manager like that you want to play for him and do well."

For Defoe, first impressions have had a lasting impact. Villas-Boas was unequivocal about his plans for Defoe from day one. "In pre-season obviously there was a lot of speculation about me and whether I was going to stay or leave, and I had a meeting with him and he said: 'I want you to stay. Last season you should have played a lot more than you did. I was watching the games, the goals you scored. A player of your quality, I need you at the club.' For me that was such a big thing.

"It's always difficult for a manager coming into such a big club," Defoe continues. "Obviously it's difficult for André because he was at Chelsea and things weren't great there. He's come to Tottenham and everybody's looking at him. Even before the season started a lot of people were doubting him, which was harsh. You've got to give everybody an opportunity. What he has done so far has been brilliant. All the lads love him. He's got great ideas. He's really organised."

Defoe feels that Tottenham have made a statement about life under the new regime in the past week. A convincing three points against West Ham (helped along by a couple of his goals against his former club) followed by victory against Liverpool has had a transformative effect. Defoe describes it as "massive".

Football has been his anchor during a period in which he has had to deal with trauma in his personal life. Over the summer his father, Jimmy, died from throat cancer, and his cousin, Hannah, was killed in a freak accident while on holiday. He remains deeply affected by the death of his half-brother, Gavin, who was attacked in the street in 2009 and never recovered from a blow to the head. "It's something you think of all the time, to be honest, when you're on your own," he muses. "The only time you don't think of stuff and you feel at peace is when you're playing. When you're on the pitch, you're in a different world."

It helps to do what he can to help kids tempted by the wrong side of the tracks. This week Defoe spent an afternoon chatting to young people who were trying to stay out of trouble, or piece their life back together, with the help of the Prince's Trust. He recounted the story of his old friend Kacey Ashman, a boy with spectacular footballing promise with whom Defoe once reckoned he could conquer the world.

"It was always me and Kacey," Defoe recalls. "We played for Newham district together and then we played for Charlton. He went to prison and when he came out, because he was so special, one of the coaches moved Kacey into his house in south London and tried to get him away from the streets, and it just didn't work. I would love to have seen what he would have done. I reckon he would have been playing in the Premier League. He would have played for England. He was brilliant. Brilliant …" When Jermain was making a name for himself as a teenager at West Ham, Kacey was sentenced to eight years in a young offenders' institute for burglary and GBH.

Defoe is acutely aware of how his life might have turned out without the crucial factors that kept him moving in the right direction. His own drive and good sense pushed him (the tattoo on his arm peeping out underneath his T-shirt reads "Hard work + Dedication = Success"). The other unstoppable influence was his mother, Sandra. Defoe remembers how she would firmly tell him to go to bed at 9pm if he had football the next day. "I'd look out of my bedroom window and see friends of mine kissing some girl. I'd say… 'Can't I go out for half an hour?' She said: 'One day you will thank me.' I thank her every day."

Sandra met Jermain's father a long time before he was born. Their courtship is the stuff of family legend. "My dad always used to wait for her outside school and she used to walk straight past him, playing hard to get," he says warmly. "They were together for about 10 years. And then, as it happens with relationships, they split up. It was just me and my mum at that time. My dad wasn't there as much when I was younger. And then as I got older and I started playing football, playing for West Ham, I spent more time with him. It wasn't the best relationship, if I'm honest. I was always closer to my mum."

The balance changed when his father was diagnosed with cancer. "You get together and you just try to bury everything," Defoe explains. "I thought: 'At the end of the day, that's my dad and I want to be there for him.' I was with him every day. I was finishing training and just going to the hospital, being with him. When I was away with England in the summer, Roy Hodgson said to me: 'You should be with your dad. It's important. Get a car. Just make sure you're back for the meetings.' That time was great. It keeps me going, remembering the good times."

Defoe has a remarkable way of maintaining a positive spirit despite the sadness he has had to absorb. Football has helped him in some respects, giving him a focus to keep doing what he loves with the maximum amount of dedication and appreciation.

He is thinking of doing his coaching badges soon, as he wants to be ready to continue to inspire more young people beyond his playing days. He is a big believer in having someone to look up to, to give you encouragement. For him, it was Ian Wright, and he still seems a little starry-eyed when he recounts how he signed for West Ham at the age of 16, and Wright took the time to stay behind after training to practise drills with him, and pass on tips designed to hone a marksman's eye and develop his cunning. "I still watch Wrighty's videos sometimes," he adds.

They are traits he puts into good use today. Defoe bucks the trend in modern football as a little lone ranger. Most teams prefer a bigger physical presence to lead their line, but all five feet and five and a half inches of Defoe is trusted to head Tottenham's attack. "The key for me is movement," he says. "When the ball comes into the box, or when the wide players get it, that's where I have to be clever and make my runs. That's where I come alive."

As ever, he will be razor sharp, ready to dart and pounce at just the right time, come kick-off against Fulham at Craven Cottageon Saturday, hoping for another goal to add to his wall chart.

Jermain Defoe was speaking at the Prince's Trust Sport Youth Forum at West Ham United, in partnership with the Premier League and the Professional Footballers' Association. The panel, including Tessa Sanderson and Rachel Yankey, spoke to an audience of young people, who are all supported on the Trust's courses, on the theme of "reaching your goals through sport" and explored the legacy of the Olympics. The Trust works with the Premier League and the PFA to deliver its football initiative to thousands of young people across the country. The partnership, in its 15th year, has helped more than 20,000 young people with the support of more than £8.5m of funding.