Welcome and hang on for the ride -- literally and figuratively -- as this forum will provide more than you expect!
Good thought on doing tires first. Although, if you are going to get serious modding, first go out and see what you can do and how you'll use it as Panthermark said.
That said, tires were my first mod and I chose Duratracs per the consensus of this forum. A year later and -- truly -- THE best AT tire I've ever run on a daily driver 4x4. I'm running 265/70-17C Duratracs and saw no gas mileage penalty from stock, FWIW.
I'm old school and want functional mods, if I mod. i.e. the mod needs to earn its keep. My immediate second mod were ACE rock sliders which are priced right, built to handle the Hulk climbing in/out, and look great while being invaluable protection from doors in tight parking lots and rocks/trees when off-pavement.
Your needs may vary, but my third mod will be bumpers and new higher-rated springs to offset the weight and maintain my current ride height; I don't need/want a big lift. The bumpers are for the added protection of the commuting jungle and a more stable climbing point for my frequent field (literally) work. Good luck!