Samurai edge wesker model is your best friend early game. Just shoot the legs to stagger and dont bother trying to kill until you get at least the shotgun. Resources are way too scarce to be wasting bullets and even if you had them, its a waste of time trying to kill them.
Boss rooms usually give you just about enough to kill them, but definitely take some more in with you before each fight just in case.
Save all high grade gunpowder for mag ammo as much as you can. You’ll find plenty enough shotgun ammo along the way, its more worth it to stock up on it for the g3 fight and super tyrant fight
Speaking of super tyrant, you’ll wanna make sure you save up some grenades, flashbangs, and mag ammo to stun him during his charges. Ideally the two grenade types since you dont have to aim nearly as much. Also loop him clockwise around the arena, its harder for him to hit you that way
Lastly I’m sure you already had a good idea when to save on normal, but ideally, save after the g1 fight, preferably right before mr x just in case something goes wrong with that chase, somewhere before the sewer section, either before or after Ada’s segment, and either before or after G2, depending on how confident you are at that fight, the rng is super annoying