I make lists for my day or week, depending on what it is. I give myself some free time when I cross things off my list, and I get more free time if there are less things on my list.
For example, with the snow today I am off and have a lot of time to do stuff. I gave myself a break and slept in until 10:30 then took a shower. So today I have this list:
Formal Orgo lab report
Catch up on Orgo lab notebook
Read Ch. 11-12 Orgo
Physics HW 5
Finish EK 30-minute Bio exams (I have 2 left)
Review Bio topic notes.
This will keep me busy until bedtime, with breaks in between for food, bathroom, attention to my husband, etc.
If I actually had classes and worked today without being canceled by the snow, I would cut the list by 1/3. Saturdays are typically full-list days (8-10 tasks), Sundays half-list days (4-5).
My lists don't always consist of school/MCAT study either. I add my work tasks, errands, etc. on the lists too, because they would be neglected if I didn't!
It must work because my friends are always amazed how I can handle school, work, and MCAT study and still have time to talk/go for coffee/chat/etc. I'm also a good multitasker on the computer and can flit between programs such as this and work easily.
There is a simple program called "Stickies" that I downloaded that lets you create yellow "sticky notes" on your desktop of things to do.