a couple tips that have worked for me:

1. set a timer in 1/2 hour incriments, take breaks in between
2. make lists of what you need to do, broken down into little steps. following lists helps me
3. figure out how you learn best (auditory, visual, kinesthetic) and switch up how you are studying
4. ask for help from the teacher if you feel like the assignment is too overhwhelming (i find that i tend to procrasitnate and not be able to focus if i dont even understand what i am doing in the first place)