Chat, chat, chat about the story. The more chat, the more understanding develops!
Have books that do things (touch and feel, tabs, flaps, noises) to promote attention.
Add a pause to every page and watch for what they are interested in.
Try not to ask lots of questions. More comments make story time fun.
Sometimes you don't even have to read the book! Say the sounds, sing the book, pretend to be the character, pretend to eat the food, say bye bye, say hello, do the actions.