Oh one more tip, itsme!
Regardless of whether you use my method or pmbmsus method (which is probably better), I advise that you keep a log for yourself. Keep track of your reps and how many sets you did. Date each entry. Make a short note each time you work out, like "I felt really good today" or "a bit of a cold"... Keeping track of it will keep you motivated to stick to your workout routine and the more you do it the more it will just become a habit and not just a workout. Another thought I have is that if you make out a chart (like, in excel or something) and then you PRE-date each entry, if you get lazy one night and then see a blank spot on your chart it will "guilt" you into not forgetting or skipping.
Also... Always set a goal when you workout, before you start. Say to yourself... I will do 7 pushups tonight. Or... I will do 20 incline pushups... If you are not feeling well, just try to do what you did the day or workout before. If you feel really good, get a little ambitious and go for a bit extra.
You can also reward yourself for stellar performance. I don't know what a good reward would be for you but just pick something... like... treat yourself to a nice dinner or something.
Well, hope those suggestions help you out!