Source from: http://www.gamesinasia.com/preparing-for-diablo-3-reaper-of-souls/

I had the chance to test Diablo 3’s first expansion Reaper of Souls over the last few days, and I have already listed 10 reasons why any Diablo 3 player will probably love the expansion. But now, having completed Act 5, there are a couple of things I learned that will be helpful to current Diablo 3 players. If you play by this list when the game comes out (assuming Blizzard keeps most of the stuff we’ve seen at the early beta preview) you will save yourself a lot of time, energy, and money.

Don’t!

1. Don’t buy or farm for any items until the expansion comes out: if you’re spending money or time farming for the legendaries in the current Diablo 3 set up, then I’m afraid you’re wasting your time. Pre-expansion, my unbuffed DPS was about 120,000. Once I ported my Barbarian to Reaper of Souls closed beta, it dropped to 70,000. After completing Act 5, my unbuffed DPS is now at 200,000. Get what I’m trying to say here? If you’re spending thousands of dollars on items, then you will be deeply disappointed. In Reaper of Souls, it seems like all items at Act 5 are powered up. I found two legendaries along the way and am using both now. So, please don’t waste any more time and money. Save it for Reaper of Souls.

2. Don’t pay for craft gems until the expansion comes out: Good gems are of abundance in Reaper of Souls. So don’t pay for them now. In fact, you should sell them while you have the chance!

3. Don’t salvage your items because of one lousy stat: Reaper of Souls allows you to enchant items, turning one of the item’s stats to another. The available stat to replace the lousy one seems to be randomized. But if you have enough gold to fuel it, you should get the stat you want.

Do!

4. Play only your main character: In Reaper of Souls, all of your side characters share the same paragon level as your main hero. So your time is better spent just playing your main character. Wear your experience bonus gear and try to hit a high paragon level. It will make transition to Reaper of Souls easier.

5. Keep your best shields: With Crusader as the new character, shields will be something of value, finally. The Barbarian could also use a shield as one of the passive skills is ‘Sword and board’ which lets you gain 20 fury for each block made. This free flow of fury means you can easily spam your ‘Hammer of the ancients’ skill.

6. Pick up gold: Gold will be important in Reaper of Souls. There’s no auction house but gold will be used to craft and enchant items, and I believe many of us will be doing that pretty often. Simple actions like taking out a gem from your item will not be cheap either.

7. Sell your items: Have a bunch of legendary collectibles in your stash? Sell ‘em. I’m serious. Looking at what’s dropping at Reaper of Souls makes the current Diablo 3 legendary items seem meaningless. Legendary drops in Reaper of Souls will be account-bound so you can’t sell them anyways. The only way to make quick bucks is to sell your current legendaries before it’s too late!