Read, read, read everything you can - including junk (like romances, paperback mysteries, etc.)
Young Adult Fiction can help you get started. It's going to be a drag, probably, to read it as an adult, but it will help develop you reading skills, then you can move on to richer reading resources.
When I was a young teacher, I used Harlequin romances to help girls in my classes build their reading skills...
Really, reading stuff that interests you, and then continually challenging yourself to read something just a bit harder (you'll be surprised how fast your skills improve), is the best way to improve your comprehension skills.
Actually, INTEREST is a huge boost to learning. It's not just about the time you put it... neural connections fire when you're reading or learning about something interesting to you... neural connections that make learning and improving skills develop much more rapidly than they would otherwise.