For a game so merciless in some areas, crafting in RE:7 is surprisingly easy going. All 'recipes' consist of only two components, require no special equipment or crafting stations, and no time to execute. Nearly have your loot is going to be in component form, so use these combinations to make the most of your resources.
Chem Fluid + Herb = First Aid Med
Chem Fluid + Gunpowder = Handgun Ammo, 10 bullets
Chem Fluid + Supplements = Psychostimulants
Chem Fluid + Solid Fuel = Flamethrower Fuel, 100 units
Gunpowder + 10 bullets = Enhanced Handgun Ammo, 5 Bullets
Strong C.F. + Herb = Strong First Aid Med
Strong C.F. + Gunpowder = Enhanced Handgun Ammo, 10 Bullets
Strong C.F. + Supplements = Grenade Launcher Neuro Ammo, 2 rounds
Strong C.F + Solid Fuel = Grenade Launch Fire Ammo, 2 rounds
Note that there is an achievement for crafting all the recipes that use Chem Fluid and Strong Chem Fluid (1st Place at the Science Fair).