One of the ideas that has helped me a lot in stretching is having a specific goal. If you stretch for general flexibility, that is good, but you will find your program will feel "flat" after a period of time. That is when most folks stop stretching.
I recommend having a specific goal (to be able to get into lotus, splits, plow) as the carrot dangling in front of you. If the goal is to get into lotus, for example, after attempting the position, you will realize the limitations involved. Now, you have something to work for, and work at. You can find all the stretches (not just lotus) that stretch various muscle groups to allow you to get into the position. You will find your own "workarounds" that allow you to realize your goal. For example, I found that really, really, working on my hamstring stretches, allowed me to get into lotus. My "workaround" was to spend DOUBLE the time stretching my hamstrings before attempting lotus. I spent weeks at my "workaround" before pushing myself into lotus. I still like to do that!
PS: the "workaround" is not a license to do a stretch incorrectly until you get it right (for example, in a seated hamstring stretch to let your head hang, your back curve over, your leg bent. ) The workaround is picking associated stretches and doing them correctly.
So, make a goal, find your limitations, and you will find your stretching will improve tenfold!