Ok. 2 level 4s down for me. Venasaur and charizard. I can help.
You're timing out right? What's your level and how many are attacking?
I promise you more success will come for trading out guys you wanna fight with for tankiness (like blissey, snorlax, and eww-don) for straight up glass cannons.
When you time out, it's because your not dealing enough damage. However, you timed out. You didn't "lose". It means he wasn't dealing enough to you either. You might have even had another guy in stock not even out to battle.
Glass cannons. Alakazam makes it in almost always. Im fortunate enough to have a perfect fury cut scizor. He's awesome. They both came in huge against venasaur (psychic is SE on poison). Hell, flareon has the highest damage dealing moves in the game. If you really want a guy to just knock a large chunk away before he bites it go ahead.
To those awesome glass cannons you add the best type hate you can. Throw/Edge Golem, vaporeon, alakazam, venasaur, charizard, executor...
Depending on who your facing. Look to the main site.
Even with that. It's tough. Watch the timer and relate it to the health bar. A quarter of the time gone and you need to have a quarter of the health gone. Half/Half and so on. Early game, and when it's not too time consuming get your dodges on specials. But at some point (for me anyways) I had to let that go and tell everyone to stop dodging and bash face.
Special Note: Bosses crack their specials quicker. This venasaur hit solar like it was a water pulse and I'm like how?! Oh. Theres 8 of us attacking him. All that damage is sky rocketing his special bar. So...account for that.