I think, regular coaching classes for competitive exam/ NET are out of your teaching schedule, but, however, there may be weekend courses that you can attend.
If that too out of your timing, what I can suggest you the following strategy.
1) First collect previous question paper. Without any preparation, try to answer it. This will help to assess your competence.
2) Note the subjects that you are not comfortable or not condifent
3) Make a schedule for nearest exam date ( for NET.. December) and follow it.
4) Take important notes and paste them everywhere your eyes often reach ( like, near to your dressing table, washing area, kitchen wall.. on dinning table.. bedroom.. etc.. ). The good part of it is whenever you see it, you try to read it and remember it.
5) Finally, be confident and tell yourself "You will survive"
Write us back once you find this really helpful. and keep update your progress.