I don't have a study timetable where I have exact times to which I must stick. Instead, at the beginning of the week I make a list of things I want to acheive that week (Like write notes for the first two parts of the chemistry syllabus, or do 1 english past paper). Depending on my mood, I'll sometimes plan what I want to do from that list every day, but sometimes I just do it systematically, going down the list and finishing 1/6 of the work every day.
I find this better as I suck at estimating how long something will take me to do, and I get stressed out if I can't complete something in the time I've allowed myself, and I won't start a new thing if I finish it before the time I guessed I would because well, it's like an excuse to have an unneccessary break.