Firstly find some time, (preferably a good few hours) in which you will free from distractions. Secondly, find the best place for you to revise. This may be your bedroom, Dining room, or may even be your College's library (Or High school/Uni). Personally, I find studying at the library is more productive as its quiet, and everyone else around you is working so its kind of motivating, at least for me. Thirdly, you'll want to have a plan of what you are going to be revising, and you need to be specific as possible. For instance, what theme/topic will you aim to cover? This is where a revision timetable may come in handy, however for me personally I just make a mental note in my head.
These 3 steps should be a good start for you to start revising, however if you give me some more details like what you're studying for (GCSE's, A Levels, Uni) then I may be able to help you more. If you're "busy schedule" is because you are working part time, I would strongly advise you ask to cut back on hours, and reinvest those hours into studying. And even if it isn't work, try and make your routine less busy, trust me it'll make all the difference in revision.