I use a day planner (I have to remind myself to use it!) and a watch that has vibrating alarms (I work in a call center, so beeping isn't a good idea) to remind me about medication. I also try to note how long it takes me to do something or go somewhere. I am one of those "early people" (I think I've done this out of an irrational "phobia" of being late) and I am getting better about not getting places quite so early, but not cutting it extremely close either.

Try writing down your routine for a couple of days. Write down what you do and how long it takes to do it. Once you have an idea of that it will be easier to "schedule" your day and manage your time. PM me if you want a bunch of ADHD sites I have found helpful. They often have great tips for different ADHD "issues".