- The Alien is programmed to seek you out if you hide in one spot for too long. Even if you are totally invisible to its patrol area it will find you eventually. You want to be hiding only long enough to lose the Alien, then move on. IIRC this is made even worse by crouching? Try to just walk everywhere.
- Save points have to recharge between each use, so don't be overzealous with your saving.
- Unless you are in a very cramped area it's perfectly okay to just sprint past androids.
- In grand horror tradition, Medical is the worst part of the game. Don't be afraid to pop a lot of items while going through it.
- Keep an eye on ceiling vents. If you see drool dripping from one, the Alien's lurking right there and will grab you if you go underneath it.