For time management, I find it useful in the mornings to plan out the rest of my day in detail. For example this morning I woke up and planned out my day on my way to work-my plan for the day is something like this: finish my experiments by 1pm, eat, read a protocol, chill for a bit, leave at 3, go to library and work on presentation until closing (7pm), go home, eat, work out, go to cafe & work on a research proposal until closing time. Don't need to write it down, just keep it in the back of your mind. It's important to have a realistic expectation of how long you will do each task, otherwise you will fall behind on schedule
For maintaining discipline: I am awful at discipline, but what I've found to be useful is to physically relocate myself to an environment where I can be more productive (e.g. studying at library, writing word doc in cafe, NOT studying at home because I know I'll just procrastinate). Hope this helps