The single best thing to do, I think, is to talk with the teachers. Tell them your concerns, ask them for specific guidance, and follow up on everything you say to them. If you promise to get your in on time from then on, for example, do it!
A second thing to consider is to monitor your own time (or get someone to monitor it for you) so that you complete all of the assigned work on time in a fully acceptable manner.
In my experience as a teacher, nearly every instance of a F can be traced back to a student not completing all of the assigned work. (Of course, there may be underlying reasons that a student isn't completing all of the work. You may have to reflect on what's contributing to the low grades and, if possible, bring a counselor or other expert into the discussion.)
I think that by asking the question, you're already moving in the right direction. Talk with your teachers, family, friends... with everyone. Get people on board to help you succeed.