It really depends on how long after a positive OPK you ovulate -which can differ from person to person and even cycle to cycle. It is possible that having sex tomorrow will be enough, but it's not certain.
Charting definitely helps - it confirms ovulation for you. Unfortunately, it does so after the fact, so it doesn't help you time sex, but that's what OPKs are for. Check out fertility friend for charting your BBT.
As PPs said, read the newbie link at the top of the TTGP page. It has lots of helpful information.