I could train a chimpanzee to tune a rear derailleur but front derailleurs can be tricky.

My advice is to go to the Park tool website. You should be able to find a set of step-by-step instructions for installing a front derailleur. Since you've obviously been struggling with it for awhile, assume that everything is screwed up. Disconnect the shift cable from the derailleur and pretend that you are installing it for the first time.

Step 1 has to do with the position of the derailleur on the seat tube. Before doing anything else, make sure that's as perfect as you can get it. My experience has been that whenever I've had a lot of trouble adjusting a front derailleur, the ultimate problem was the position of the derailleur on the seat tube.

Follow the rest of the steps IN ORDER because each adjustment affects the subsequent adjustments.

Good luck! The good news is that after you get it right, you will have the sense of accomplishment at having figured it out yourself.