One of the most important things to remember about temps, is that they are meant to be looked at in hindsight. You won't be able to look at your temp every morning and know that you will O the next day. This why often times (and I recommend) that women use OPK's along with their temping.
Yes, sometimes you will get a dip the day before you O, but not every woman and not always. After you O, (the egg leaves the follicle) your body (the follicle) begins to produce progesterone. Progesterone is what makes your temps rise; it is called the warming hormone. It is too late to BD after you have a sustained rise in temps (never stopped me though) because the egg only lives for about 24 hours.
By temping, you can pinpoint your average O date pretty accurately, especially if you have a hard time with OPK's. This gives you a starting date for BD'ing (about 3- 5 days before your average O date) and then once your temps have rose you'll know you're in the TWW. Temping is also really useful for women with very long cycles.
Feel free to ask any more questions. I also highly recommend the book Taking Charge of Your Fertility by Toni Weschler. It's a good, easy read and will make you an expert at temping =)
SSBD!!!
Ok...here it goes....BBT 101.
When you ovulate you will see a dip the day before you ovulate...usually...then you will see it go back up the next day signaling that you ovulated. I would use OPK's to be sure you are getting the correct day.
When ovulation has occurred your temps will rise but then they could take a dip about 4DPO and then again at 7-10DPO. Some dont dip at all though. I found temping to never be an exact science.
You need to BD a few days before you O and a couple days after. Those are the best times. Usually you have about a 4 day window but you technically only have about 24-48 hours in a cycle to fertilize an egg. Bedding the day before your O and the day of your O is best.
I started bedding about day 9 of my cycle then every other day until I got a positive OPK then I would do it daily for about 4 days.
Keep in mind each month my temps would change differently than the month before which would frustrate me. I ended up using the OPK strips and got pregnant the first try using those. Good luck to you.