Routine
Always start with a clean slate by preparing your skin. Your routine should include steps in correct order to create your desired look.
Here are some sample routines
Primer
to smoothen out skin texture and allow powder to stick to it (sometimes special eye primer, sometimes blemish balm "BB" cream, sometimes tinted moisturizer)
Foundation
to make complexion look more uniform, hides some blemishes. for powder this is where brushes are useful. also used to hide beard shadow [link here]
Concealer
concealer, color corrector, undereye corrector - to hide discoloration and imperfections. repeat steps 4-5 for stronger disguise
Contouring
contouring, highlight, bronzer, blush - this is to cast shadows create contrast and give the appearance of better 3d shape
Lip Liner
to create a good outline and shape
Lipstick
lipstick or lipgloss - to make them pop and look pretty
Eyebrow pencil
eyebrow pencil, gel, powder - to make it defined, give it nicer shape and fill out gaps
Eyeshadow
to enhance and create colorful displays on your eyelid. usually sold in palettes with bunch of colors. brushes are crucial but there are stick options.
Eyeliner
eyeliner pencil, liquid felt, gel - make them bigger, improve canthal tilt, wing it like an egirl
Mascara
to darken, extend and curl your lashes. use of lash curler before eyeshadow is recommended