As soon as you are able, get you a carbine rifle and force gun combo. Mod it with acid bath and a damage mod. Plug damage/reload, clip/reload and ROF (rate of fire)/clip or ROF/damage circuits into it as you get them, keeping an eye on the stats so you don't accidentally plug in a reload when you don't need to. Win the game. Rinse, repeat.
If you want to stock up on items for harder playthroughs, rip through the game on casual. The amount of any particular item you get is directly tied to the difficulty level you play on. Harder = less. Don't be afraid to use stasis, but don't rely on it. Sell stasis chargers for resources. Always carry one or two tungsten torque bars for torque doors. Don't forget you can rip the arm-blades off of Necromorph corpses with kinesis in a pinch. Once you unlock the scavenger bots, they will be your best friends in finding resources. Listen for the wobbly noise as you're tromping around. Also, big up your RIG armour and health as fast as possible. Make frequent trips to benches to unload gear, particularly in the early game, as your inventory space will be limited.
And lastly: The outside space areas always respawn their loot when you come back outside. Farm that shit, there is a ton of loot just floating around out there. You won't regret spending the time doing so.
I think that's it, anyway.
EDIT: Oh yeah, stomp corpses regardless of whether you think they're dead or not. Sometimes the game doesn't cause them to drop loot when they die unless you stomp them, and it's very aggressive with the body culling. If you don't think you can get to a body before it's culled, just shoot it and move onto the next enemy.