If you post an example of your army list and an example(as close as you can remember of your opponents), we could better help.
Other than that, it seems likely you aren't playing with enough terrain, as a game with KoS, should go...
Turn #1. Move Fast(up to 24") and hide behind a piece of terrain.
Turn #2. Move 12", deploy, shoot and assault.
Other than that, armour plates, red paint jobs, turbo boostas(grot riggers are mandatory in KoS, so I'm assuming you already have those), and a KFF, mekboy Tools, and grot oilers on a mekboy in a burna squad or a big Mek in a battlewagon, should enable you to survive until you get there. On a battlewagon, the force field generator is great as it doesn't slow you down like it would on a truck and gets rid of your vulnerability due to open topped.
As for weapons, rokkets and burnas all around. Don't bother with the big shootas. I really wouldn't ever take big shootas in any Ork list, unless you were specifically fighting a horde list, and maybe not even then. But that's just me.