How Do I Follow Through On Tasks?

I stink at follow through! I work at an elementary school and oftentimes, I need to call parents back, complete tasks for teachers, do research to get assignments done, call district employees, meet with school employees for scheduling, redirecting, and sometimes conferencing over job performance, and assist with student discipline or emotional support. I find it difficult to follow through with all of the above. I create lists, but I find I’m still not fulfilling things I have started and can’t get through them. What would be the best way to complete these tasks all the way through? Thank you!