Some nids and wolves and some necrons

So, yesterday, I had the chance to get some 40k in. Played a couple games. Didn't do so well.
First game: Space Wolves, 'Nids, and me(Tau).
Different space wolf player than I usually play. Game came to a draw, but I definately lost.
First 3 turns were a lot of terrible dice rolls. by turn 4 I was so decimated that I couldn't do much. I did have a squad of firewarriors hidden in a devilfish. Unfortunately, the nid player knew enough of me to take this out. I sneaked my warriors by, but his Trygon Prime was able to circle around and take them out. The space wolf player lost his troops, leaving the nids with a single genestealer squad to take the objective. Luckily, the SW Land Raider took them out, leaving nobody to claim the 3 objectives, giving me a draw. It was rather pitiful. It seems that my tricks are all learned, and that I can no longer play an all comers list. Need to change it up, seems to be the problem with playing the same guys all the time.
Second game was even worse(believe it or not). Forfiet on turn 5. This one was capture and control as well. Using corners, I started with the same dismal rolling. My problem here was more of ignorance than anything else. Against 'crons, I have to change my play style considerably. My standard starters out with about half in reserve, including my plasma suits. Against necrons this setup needs to be reversed. I need to keep my hammerhead in reserve(*gasp*) and put my plasma, vespids, and other low AP weapons out. Even though I was playing the SW player, I think I could have done better by having my HHs show up later, leaving them alive and in better shape when the monoliths arrive. Not having the rail support to hit those monstosities when they come out left me in a bad spot(stupid no melta).
Some changes I made recently:
Drop the FW Devilfish for more FWs
Kept the Piranha, but thinking should go for a Carbine squad. Melta isn't doing it anymore.
Cutting out seeker missiles, been using lights for targeting.