I have ad/hd myself, and am generally not really that into reading to be honest, but since it contributes to a large part of how society functions, well... you get the point :]. Here's what helps me:
1. When I read, I get distracted really easily, especially since I don't really enjoy it, which causes me not to properly take in the information, leaving me frustrated and bored. So when you arepracticingg reading with this student, try to create a relaxed and quiet environment with the least amount of distractions possible.
2. When in class (I'm still inhigh schooll), we are assigned a large reading assignment or a page to read, I quickly get overwhelmed, causing me not to be less interested, which will stop me from comprehending the piece properly. This generally happens when everything is all the same colour, with small fonts, and look like long paragraphs. What helps me to be more motivated to read something is when is isn't too much (or at least doesn't look like it). You can do this by using dotpoints, very concrete headings with short paragraphs in fun fonts and styles, and make making important things stand out like extra info boxes at the bottom, pictures, etc. The big idea is to make sure that the reading part is done in small sections that are easily do-able, other wise attention will shift very quickly.
3. If you need to test comprehension or something, so shorter and more relaxed little tests that seem less hard to do, more often when the subject is still fresh in the mind. one of the things I really struggle with isorganizingg my written work so maybe it's a good idea to experiment with different styles of testing, eg. written, oral, filling in bubbles etc.
4. Often with adhd students (well, for me anyways), motivation plays anenormouss part in how much they enjoy tasks, how much effort they put in etc, and generally it takes a lot more motivation than other kids because they switch attention (and thus motivation and interest), so quickly because they're distractible. So try to motivate the student. for example offer different things depending on their age, for younger children things like stickers, small toys etc work really well, and for older students things like a lot of recognition of achievement, a positive call, email or not home to parents, a break in eg half an hour, or after completing a certain thing. When the kid is motivated it'll be very likely to see improvement.
I can't think of anything else, but I hope this helps. Good luck =]
ps> My bad you meant stuff to do, instead of how to do it...
when I was younger I loved playing very fast paced games so maybe you could ecorporate words and spelling stuff into a fast game or boards game with some sort of achievement like tokens or something.
you could try "doing" activities rather than "watching", or "listening" activities. For example you could take them for a walk outside (the movement will help them think too) and point to different things and ask them to spell it for you, and then put it in a sentence for you. If they do this correctly they earn a token or something and then you could give some sort of award is a certain amount of tokens is reached. The key is to make it more fun and make it look very different than the scenario of a boring classroom, behind a desk, with a reading task in front of them.
Try relating the the lessons to the students interest. Like for example when I was little I was obsessed with spongebob, so my teacher made spongebob themed worksheets, bought cheap litlle spongebob rewards like a spongebob pen or something. this really helped me to fully engage in the lessons :] You could try making a quiz about their most favourite thing, for them to fill in. This would be very effective, as they are likely to know the answers very well (since it's about their intense interests) and at the same time they'll be practising their reading and writing skills. Or if they are visual learners you could let them watch a short video or episode (for me spongebob :D) and get them to write alternative endings to it?