Preserve Flares:
Keep your flares forever with this trick. When you notice the flare is about to go out, simply highlight another object then go back to the flare.
Preserve Blood Test Kits:
Don't waste your blood test kits on your team members since they get infected randomly and mutate within seconds of being infected. Your best bet is to use the test kits to prove that you are infected to keep your buddies loyal to you.
Preserve Your Medics:
Try to keep your Medics alive! Their ability to heal you will be invaluable in the later levels.
Preserve Bullets:
Don't reload mid-clip, you'll lose the bullets still in the clip.
