I use foundation on everyone, and I only use liquid or cream foundations (MAC F&B, MUFE HD, Boots Lifting and Firming, and Mehron Celebre HD). Which one I choose is based on what I think will work best with their particular skin type or skin tone. Where I make different choices to compensate for oily or dry skin is in the moisturizing and foundation primer choices. I also choose foundations by how sheer/covering I need it to be. Otherwise, I follow the same method regardless of the person, just change how much and which specific products I use to best compliment them individually.
The steps I go through are:
-clean face thoroughly
-apply moisturizer if needed (currently I favor Cerave, typically the PM formula without SPF)
-apply foundation primer if needed (MUFE HD primer)
-apply lip moisturizer (should be done early in process to allow to soak in)
-apply eye primer (UDPP is my preference)
-apply upper eyeshadow
-apply brows/work on brows
-apply concealer if needed
-apply lower eyeshadow
-apply lashes (individuals, not strips)/curl lashes if needed (I rarely use mascara on upper lashes and prefer to just add more individual lashes to make them stand out more)
-apply eyeliner if needed
-apply mascara to lower lashes if needed
-remove excess moisturizer from lips and apply lips
As for lips and eyes, you can make them work together and have them both be bold, but usually it is easier to pull off one or the other with a bolder look. A strong lip often works really well with a nice eyeliner look, while a deep smokey eye will often work best with a nude lip. Really, it just depends on what you like and what you are after. There are no real rules about it.