I could go on forever about this, but I'm going break it down in to three, very simple steps that will elevate your playing massively.
1) Watch Wak's Advanced How-To-Play videos, and master those techniques before carrying on to step two. Here are the links:
Part 1:
http://www.youtube.com/watch?v=4n4s5yB7ZkE
Part 2:
http://www.youtube.com/watch?v=xiZLs2doK8E&feature=related
Part 3:
http://www.youtube.com/watch?v=PFmGIOcWdsM&feature=related
2) Watch videos of good players. RaynEX, Bam, Mew2King, Cactuar, and PC Chris all have smart and technical Foxes that are worth watching. Search them up on youtube, watch what they do, and try to imitate them. Practice them so you can do them on command. There's a really good set between Cactuar and Darkrain (a very good Falcon player) starting here:
http://www.youtube.com/watch?v=U1WTIRfal8M . There are links to the rest of the matches on the side of the page.
I could tell you everything, but you learn from doing research yourself, and that's when things really stick and become applicable to your playing.
3) Finally: GO TO TOURNAMENTS! Find other players near you and, if you haven't already, start getting together with them and going to the tournament that community hosts. This is where you apply all the work you've done, however much that is (even if it was only a few sessions throughout the past couple weeks) and test your skills. Here is where you learn from people and ultimately place yourself in the situation where you will get better. Also, from playing with you in person they will be able to tell you so many more things than I can to help you.
I hope this helps somewhat. Not to sound to presumptuous about the third comment, as you likely are already attending tournaments, but I thought I should add it in anyway.
Good luck.