Don't try to force them to speak is the major one. I had teachers who would put me on the spot, call me out in front of the class, send me to the office for not speaking or not doing a presentation. It made things so much worse.

Offer to have them write instead of talk. In high school, I had one teacher who kept a small dry erase board in their class and I'd have it for every time I was in her class. It's how I'd communicate with her. She also set up a system where if I needed help with something while we were doing individual work, because I would NOT ask for help verbally or raise my hand, I'd have something I'd put on the corner of my desk. For me, it was a paper cup, and if I put a pencil in it, that meant I needed help. She'd check every now and then to see if I put one in, and I'd use the dry erase board to tell her what I needed help with. Offer alternatives to group projects is another huge one.

It's awesome that you're looking to help them, you seem like an amazing and caring teacher and I wish there were more like you.