askchapo

If you have the bandwidth, giving them pre-reading really helps. A few paragraphs of context (and maybe a vocabulary/terminology list) and background to start with, and then some questions. Write the questions so that they know what to pay attention to, and make them as specific as possible (e.g. "in section 3, when x says y about z, what does that mean?") to call their attention to the important bits and help them scaffold their understanding. A lot of reading comprehension issues come from not knowing how to prioritize information: if you're not used to dense texts, it's really hard to know what's important and what's background/filler. Some signposting about what to think about and look for can be very helpful.

ETA: Here's another suggestion. Give them annotated copies of the things you're asking them to read (either your annotations or someone else's). That is, give them copies of the readings in which important passages are highlighted, and in which margin comments call attention to or explain particularly interesting (or tricky) passages. You could even invite all of them to read a single shared copy of the text and contribute their own annotations/comments to it. Anything that increases engagement is good, and seeing what other people have to say about a text can often be really helpful.