Let your child pick which pajamas he wears, and teach him how to put them on himself (even part of the way). This should make him somewhat less resistant to the process.
Let him pick which blanket or pillow to use.
Establish a repertoire of creative methods for getting your child physically into the bed: “Through the cave” (in through the side of the bed and under the covers), “over the clouds” (flying in and landing on the pillow), or “jumping to the moon” (pretending to jump in, with your help) can make the process more fun.
If your child is sleeping in a bed and not a crib, read and sing to him while lying down next to him rather than sitting up with him in your lap. Often, just getting horizontal makes him realize how tired he is.
After reading, convince your child to close his eyes as you sing to him or tuck him in—even this simple move can show him how tired he is.
Have your child put a favorite doll or stuffed animal to bed as part of his pre-bed routine.