I recommend reading Zoning/Spacing and Other Fundamentals and the Focus & Concentration I wrote instead of this. I wrote this a long time ago, and while some of it is definitely still applicable, I think my other threads explain more about what's really important.
Tech skill is highly necessary. Whether or not it's the first thing you should work on is dependent upon the person, but you can't expect to compete against people with nearly-flawless tech skill on top of their excellent ability to outsmart their opponents if you can't control your character well enough to do what you need to do.
There are so many things that truly go in to becoming good at something. Dedication, practice, and creativity are all very important.
In fact, I think creativity deserves its own section. The metagame evolves and develops due to people's creativity. If it weren't for people coming up with new, better and/or different tactics, then the game would never change. I believe a lot of people try too hard to mimic ONLY the things they watch others do and the things that pros say they should do. This is very limiting to a person's ability to come up with new strategies and tricks that could give the upper-hand. If you play the game and constantly look for opportunities, you WILL develop new tactics and strategies. However, a lot of people will think "Oh, well I should only do short hop fairs and up tilts because that's how I'm supposed to play this matchup." If you get away from this mindset and consider all of your options rather than the options that you've limited yourself to, then you will probably come up with some pretty awesome new things.