Understand the basic building block of reading: know the sounds letters make. If you can sound words out phonetically, you can tackle even the most advanced material.
Take it one sentence at a time. Read a simple sentence from one paragraph. Explain what that sentence means. Use that understanding to continue reading.
Visualize as you read. For instance, read the sentence, "The black cat jumped off the window sill," and pause to imagine that scene. If readers can take the words and create a picture in their heads, then it will help develop an understanding of the ideas that words are trying to convey.
Break up larger sections of text into smaller chunks, which is a process called "chunking." At the end of each chunk stop and digest what you read, and if possible, discuss it with other readers.
Read for context. Read this sentence as an example: "The tangerine parrot gesticulated wildly, waving its foot and pointing." To understand the word "gesticulated," readers first understand that the parrot is waving its foot and pointing, so they can infer that to "gesticulate" is to make movements and gestures. This method allows readers to fill in gaps of understanding and to learn new things without pausing to use a dictionary every few paragraphs.