Gardeners Block...

I've just moved into a place with a wonderfully large garden space.  It probably hasn't been used in 10 years, but is nicely fenced to keep out deer and rabbits.  My problem is that I have just moved from S. Florida where I did container gardening to great success, now I'm in South Jersey and I have all this land to dig up and cultivate - I don't know where to begin.

Any tips for "digging in" and planning where to plant things?  I'm a big fan of sheet mulching, but may have to switch to a new, untried method, and actually till the soil.