One thing that I learned that REALLY helped was telling the new baby she has to wait her turn. Now I realize this sounds stupid because of course the baby doesn't understand, however the toddler does. Right now he feels like the baby is more important than him. It's time to turn the tables in his favor. So when your getting his breakfast ready and the baby wakes or fusses, tell the baby, "You'll need to wait a minute, I'm helping your brother right now." The next time say something like, "I know you need my help, but I'm helping Johnny. It's his turn." This really does go a long way to make the big sibling feel like he gets his time.
Another thing was we got our older sibling a PLASTIC baby doll (well before the baby was due). After our baby came, I'd diaper my baby and the sibling would diaper hers. When I would wash my baby, she would wash hers. My daughter quickly got the idea that SHE was Lula's Mommy and she had to take care of her baby. She even would lift her shirt to 'nurse' Lula!
Finally, I agree with the idea of ensuring your son has some "big boy time" everyday. I know your exhausted and the idea of breaking out paints or running around the backyard is probably more than you can bear right now. So take some time and go to the store. Buy about 5-10 new toys for him...crayons and a cool coloring book, stickers, a new block set, a new board game like Candyland...anything that's fun for him and easy for you to cleanup. Then, when the baby goes down for her nap, say "It's Mommy time with Johnny!" and go into your stash of stuff and make a big deal out of pulling out a NEW ACTIVITY that's JUST FOR BIG BOYS. Make this happen about the same time everyday, once a day (like the baby's am nap) so it gets built into your routine. Then play just with him until the baby's nap is over. As soon as the baby wakes say, "Hurry up! Help clean this up. We don't want the baby getting into your big boy game." My daughter LOVED the idea of protecting her new things from the baby and soon she would clean up herself while I got the baby. I found that doing this in the am worked best for us since I'd already had my morning coffee and was wide awake, and the toddler had energy and it wasn't "melt down time".
As a last point about big boy time and the lovely melt down time that usually happens before dinnertime, let him help. Keep him busy, but don't expect too much. Maybe he can set the table? put his cup on the table? put silverware out? mix some salad? I know this seems like "too much" for a 2 yr old, but the point is let him help you somehow (although don't expect it to really help), it's to keep him occupied while you're busy. Then tell Daddy when he gets home "what a BIG helper you have" and have Daddy fuss all over him and tell him how proud he is that his "little man" is helping Mom around the house while he's gone.
Usually for us, after dinner is Daddy time. I am exhausted and tend to the baby. Daddy and the kids clean up and then play. I am OFF DUTY! The kids relish having someone to play a game, wrestle with and then read to them in bed. I am usually getting the baby down and changing into bedtime clothes too.
I hope this helps. It worked for us! Good luck and congrats.