Make time to read with your child everyday. Sit down together and read a book with her. When you're finished reading the book, ask her questions about the main characters and the plot. This will help her to understand what just happened in the book you read together. You can also ask her questions about what you think would happen next if the book were to continue on. If she can develop a logical storyline, you will know that she fully understood what you just read together in the story.
Play word games together to teach her the meaning of the words she sees when she's reading. She can learn from games with a theme such as rhyming, vocabulary, and letter recognition. If she understands what different words mean and how to recognize them, she will be better equipped to comprehend the material that she's reading.
When reading a book to a preschool child that you've read together before, review what happens in the story before you begin to read it again. She should remember the main ideas, so if she can tell you a little about the main characters and the storyline, she understood it. This is a helpful way to practice retaining information with the child.
Don't just practice reading comprehension with story books. Work with your child everywhere you go. Read street signs, restaurant menus, game directions, and any other everyday items with text on them with your child. Explain to her what the words mean and work with her to be able to read and comprehend the text on these items on her own.