What do you do after you get bored? My Achilles heel has always been too much internet and distractions, and actively removing those has helped increase concentration.

Not specifically related, but I personally find that having too many options for what to do generally makes me hop between things too much. I have a theme for every day of the week, and I don't allow myself to work on anything under a theme for another day. MWF are three courses respectively, TH is backend for a side project, weekend is frontend for a side project.