When facing a Droideka, stand as close as you can to it, and directly in front of it (between its gun arms). It cannot shoot you. Kill it with melee attacks to save ammunition. Note: If there is more than one Droideka, stand so that you are in line with as many of them as possible so that the others cannot see you.
Toss two electric grenades and fire a quick bust from the DC-17. This should shut them down or put them on the ground. Additionally, to defeat a Super Battle Droid, run up to him while he is shooting at you. Then, melee him and back up before he can hit you. While he is swinging his arm, fire at him with your blaster. After he melees, he will resume shooting at you. Repeat the process until he is destroyed. If there are two SBDs, focus your team's fire on him.