Management consultants talk a lot about corporate culture, which is a shared set of beliefs about which strategies and tactics make sense. However, only fairly large companies have corporate cultures.

Smaller organizations, like start-ups, haven't been around long enough to develop a culture, nor are there enough people to create one. Instead, smaller organizations have something equally important: the "team mood."

"Even a highly innovative start-up will stumble if the general 'mood' is bad," explains marketing guru Jeffrey Hazlett, who's bought and sold over 200 companies, "A start-up is likely to succeed only if the entire team is consistently excited, engaged and positive."

In my experience, "team mood" emerges primarily from the attitude and behavior of the team's leadership. When leaders maintain an upbeat attitude through thick or thin, it makes everyone feel more optimistic and believe more strongly in ultimate success.

With that in mind, here are five ways to create a powerful and positive mood for your team:

1. Smile more frequently.

According to the latest neuroscience, smiling improves your own mood, because it tells your brain that you're happy, even when your thoughts are grim. More important, research shows that leaders who smile more often are more successful than those who don't.

2. Build an upbeat environment.

Few things are more depressing than the standard cubicle-farm office with beige partitions. (Blech!) Rather than go with what's easy, make the extra effort to have an office with personality.

This needn't cost a lot of money. I remember one start-up office where all the furniture consisted of pine planks on cinderblocks. Being there was like hanging out at a pal's off-campus apartment.

I recall another start-up that set up shop in corner of a empty factory, with all the old mill equipment painted glossy black but still in place. The place had a steam-punk feel to it even though steam-punk hadn't really caught on yet.

3. Don't hire jerks.

This seems like a pretty basic no-no, but it bears repeating because it can be surprising easy to hire a jerk into a start-up if that jerk possesses a key technical skill. Resist the temptation. No matter how talented a jerk may be, it's not worth it.

A big company can tolerate a few jerks here and there, because their corporate cultures run on automatic. One or two bad apples can't spoil the whole barrel.

In a start-up though, all it takes is one jerk to sour the corporate mood. Rather than a bad apple in a barrel, the jerk is like a dead mouse in a milk jug.

Needless to say, don't act like a jerk yourself.

4. Celebrate early and often.

This is huge. Don't wait until your product is successful to hold a big party. With a start-up you should celebrate, well, just about everything.

I'm not talking about "cake in the break-room" stuff, but real parties on a regular basis.

For example, I once worked with an incredibly prolific group of software programmers who held a weekly Friday night party in the back room of a local bar.

These "quality control meetings" (as we called them) were not only fun but created interaction between people on different parts of the project.

Ideas were sparked, and often ended up being implemented that very night, after the meeting had adjourned. Luckily most of the programmers could write solid code even when a bit soused.

5. Cultivate your inner optimist.

Some people are naturally optimistic but others (myself included) must work at it. I recently posted a recipe for achieving a positive attitude, so I won't go into detail here. Remember: your optimism is highly contagious, so it's worth expending extra time and effort to achieve it.