this is how I play as the asari vanguard:
1) try to level out everything except stasis, stasis is a great skill but the other one are better.
2) when maxing out lift granades go for range damage and the extra granade, forget about duration or the slam ability.
3)use the geth shotgun, it has high damage and long range so you can stil hit the targets at a distance, you can also charge it for more damage. and equip no other weapons to increase the recharge speed.
4)we're going for a hit and run attacks. shoot them from afar then rush in to finish the job. pop out the grandes and melee and use the shotgun.
5)don't rush blindly, it will only get you killed. resulting in a loss because your team tried to save you. you dont have nova and melee takes longer so you are more likely to get killed.
6)when using granades to kill groups try to hit a person in that group. the granade explodes on contact. dont worry if you miss they will still go of but it can be less effective.
7) using granedes and only one weapon can lead to a situation where you're out of ammo. so make sure you know where all the resupply points are and make habite of swining by them whenever you can.
go for the hit 2 addition targets with the biotic rush. that way you will stun more targets when going in.
dodge only when needed because it will drain your barrier.
train on bronze with those granades. use them whenever you can whilst training. hitting the target will mean more kills.
you can hit the cerberus shield guys by pinballing a granade via the wall. there is no faster way to kill them