I second Schofield and Sims. Love those books, not just comprehension, equally brilliant for maths imo.
DD2 reads loads and is good at comprehension so perhaps it does help if the DC reads widely. Having said that DD1 does not read at all. The only thing I can remember her reading for pleasure in the last 5 years or so are the "Twilight" books.
I find that if you make a DC read if they don't really want to do it they are more likely to skim read because they want it over and done with quickly and consequently that won't do anything to aid comprehension. I used to look for suitable newspaper and magazine articles and discuss the content with her after she had read them and/or ask questions.
I also used to get talking books from the library such as "Artemis Fowl" and listened to them together whilst we prepared the evening meal in the kitchen together. Once you get in to the story it really isn't as boring as it sounds.
It is also a good idea to start making a word bank when they come across new words. There are also good vocabulary builders such as "AE publication" but they are a bit more £££.
When DD1 started GS a few years ago the English teacher was shocked when I told her DD does not read books so it seems that our approach did work.