When reading, have these questions at the front of your head:
What type of writing is this? (genre)
What was the main idea (in that paragraph) / main ideas?
What else did it make me think of? (associations and links)
Can I picture things in my head? (visualise)
What impression did the words have on me? (reader/ writer effect)
What would I ask someone if I could? (empathy)
What words haven't I come across before? (word meanings)
What information is the author missing out? (infer)
What clues give me an idea when or where this is? (time or place context and settings)
Why did the character do / think / say that? (motive)
What could happen next? (prediction)
What do I want to find out next? (suspense)
What if ... (this bit was different)?
Here are some really good websites to keep you reading for hours: