a) never give plasma weapons to your precious yet very squishy JO's! you need them for one of 2 very, very imporant roles;
1) Ld boost. give them iron discipline and now you have a 24" base Ld8 which cannot really be modified unless you're drastically outnumbered in an assault!
2) bait! 9 out of 10 players will fall for it if you leave your 'valuable' officer and his mates as sitting ducks on your front lines! most people will want to knock them silly in close combat... you, being the cunning type, will have pulled your infantry 7" away from the officer, thus leaving a powerfull enemy assault unit in perfect rapid fire range of half your army!
b) always use support squads for your anti-tank needs! your infantry squads do one thing really well; kill enemy infantry. they shouldn't be wasted on tanks!
c) vox-nets are over-priced piles of crap... (trust me, i've crushed every vox-dependant army i've faced with either a 55pts sentinel or a 36pts remnent squad deep striking the master-vox!)
d) always specialise your units to fullfill a single role. we're not marines! we don't multi-tast worth *****! pick a single role for a unit and equip it to match...
e) never, ever feel bad about sending a squad out on a suicide mission! remember, if you lose 10 men to achive a goal, you still have another 70 or so men to fullfill the overall objective!
cheers!