Can anyone tell me how to induce labor by myself? I have heard a bunch of different things, but is there anything that works DEFINITELY?

I've heard about having sex, eating mexican food, drinking raspberry tea and walking...
Something else I have heard is Caster Oil, but I have also heard that makes you have to go to the bathroom A LOT. So, I am not willing to try that.

My husband is out of the state helping a friend, but when he gets back I plan on going on a date with him... we'll go to the mall (walking around), have dinner (mexican food & raspberry tea) and then home (sex)...

In the mean time, is there anything I can do by myself to help start this process?

How far along are you? Always, always best to let baby come on his/her own unless you have a true medical reason to start things.
You increase your chances of having problems for yourself, your labor, and your baby. Is it worth it?
The only time you might consider trying to induce labor is if you are well passed your due date and hoping to avoid a medical induction. Even then nothing will work if your body is not ready for it... even a medical induction will not go smoothly if your body isn't ready for labor to begin.
You can try the usual suggested ways... frequent sex, pressure points, perhaps walking, etc. but if you do, go with the noninvasive options. Castor oil may work for some women, but others find they just have bad cramping and have to spend time on the toilet. There is also some thought that it may possibly increase the possibility of baby having a bowel movement which you would want to avoid.
I know it is hard at the end... but if you are just uncomfortable and/or anxious to see your new baby, try to focus on pampering yourself the last few weeks. Get a pregnancy massage, spend some quiet time with your husband, take care of any last minute projects you want done before baby arrives, etc..