A few basic tips:
1. Smash-cancel with dodge or heavy melee
2. Smash primes phantoms and banshees for BE through their bubble (if specced for biotic combo).
3. Power amp and geth scanner are the best gear for the phoenix kits in team games. Cyclonics, if playing platinum.
4. Their heavy melee is an awesome tool to stagger enemies around you when you are in a tricky situation. It has a pretty huge AoE and nice damage too. And has multipliers against all defenses.
Adept:
66066 with venom
1. I find lash pointless given the way I play him. It's too unreliable for my tastes.
2. Cast singularity on every enemy before running into CQC range. Venom's ability to shoot and stagger while running makes it a very handy weapon. Singularity staggers every humanoid enemy (except phantom) which allows you to close distances as well.
3. Venom also helps dealing with pesky swarmers and seeker swarms that eat your smash meant for ravagers and captains.
4. You can release charged venom shots just before smashing (disruptor ammo helps for TBs) or just after smashing, while doing dodge-cancel (warp ammo helps for biotic damage bonus).
5. Other weapons that work well are: wraith, arc pistol, talon, csmg, falcon.
Vanguard:
66066 with wraith
1. Lash is even more pointless here, except for lulz. Charge and smash give you everything you need.
2. He's hands down the best vanguard to spec into bonus power evo on charge. Post charge, his smash hits like a truck. Always press smash button after charge, if the enemy is alive. If bonus power gets activated, almost all humanoid enemies die to that smash. If not, dodge and shoot. Very aggressive but very rewarding.
3. Another slightly different way to spec him is to go for melee evos in fitness and slap on an omni blade. His rank 6 of fitness boosts power damage after a heavy melee kill. So, charge > heavy melee kill > smash absolutely wrecks stuff. It's even more deadly if you have a pistol with power magnifier.
4. After every charge, I dodge so that I am close to a wall. Then, I use RHA and smash.
5. Other weapons that work well are: venom, talon, graal, GPS.