Monitor your own comprehension. Pay attention to your inner voices and thinking processes to understand a text. If you find yourself saying, "Huh?" or are completely blanking, stop and use a different strategy to help you get back on track.
Re-read passages that are challenging. You can do this by re-reading sections or paragraphs to make sure you're able to summarize what you've read.
Slow down. Take time to understand the text.
Read the text out loud.
Take notes as you read. You could do this in a Google Doc, on paper, on sticky notes. If possible, underline or highlight passages that stand out as you read and write in the margins. The key here is to have some strategies to help you focus on key concepts in the reading.
Don't skip over words you don't know/understand. Skipping words you don't know will just result in lack of comprehension. Use context clues to help you figure out new words. If that doesn't work, use a dictionary. After looking up new words, take another look at the sentence and "translate" it into something that makes more sense.
Start a reading group. It's helpful to talk about what you're reading with others. Talking about challenging texts may help you understand it.