As mentioned, don't fake it. If you're not digging it, pick another book or another time - it SUCKS when an adult reads in a sulky I'd-rather-be-doing-anything-other-than-reading-to-you voice. Kids know precisely what that tone means, and it breaks them.

Don't rush. Why would you want it to be over soon? You're pouring words into a kid's open greedy brain. Make it last. Five minutes more equals hundreds more words for building dreams and castles.

If it's funny, laugh! When Shel Silverstein is being a silly old bastard or Louis Sachar has gotten too ridiculous to stand, don't press on through the text - drop the book on the floor and roll around on the couch laughing. Don't you want to have that memory from your own childhood? Do me a favor and give that to a kid you know.