You must be familiar with d3itemsale.com if you often buy D3 Items. As the safe site to buy Diablo 3 Items, we can offer you the lowest price D3 Items that can meet your requirements. In addition, there are some useful D3 guides at our site. Now, you can get general tips for all classes in Diablo 3 from the following parts.

Bring plenty of Health Potions and pick up the health orbs he drops when your heath is low. (Make sure your at full health before he begins K.O Move.. Green Whirlpool things.)

- Use health pots strategically - try to keep life above 80% at all times (or whatever won't get you one/two shotted by the whirlpools if you do get hit).

-Enable Elective Mode (Options>Gameplay>Elective Mode) I think it cripples your potential, and less customization with your skills if disabled.

-A lot of players have reported that a high latency can affect the fight with Belial, so try to get your latency down as much as you can. I recommend below 300 for an easier battle.
- Items that give + to movement speed really helps with this fight to help you avoid the green circles.

-One critical thing that helped me out a lot, was to bind the middle mouse button to "move". So when the green swirls started coming, I could use that button to move out of the way without accidentally clicking on part of Belial instead.

Stay near the right side of the platform. dodge the green circles, run back to the right side. You're guaranteed to dodge his poison spray attack, which hits you anywhere else (except the far left side, but you can't really see anything and end up misclicking on belial all the time). I've also found that less green circles appear at the far edge, making those easier to dodge.

There are many others D3 guides and strategies at d3itemsale. Hope these guides could be helpful to play Diablo 3. BTW, Diablo 3 Items for sale is also available here. Don't be hesitated to buy Diablo 3 Items if you want to level up your characters. Big bonus is waiting for you!