I have no experience in Atlanta, but I will say that the one constant in any development project I have been involved with is that you need to get the land at a deal of a price. There are obviously a lot of upfront costs in development, between land acquisition, architects, insurance, zoning and variance applications and approvals, legal costs, etc. Based on what you want to build, you need to make the land purchase contract contingent on your ability to get any zoning and variance approvals prior to your closing.
As for location, as a general rule, most developers follow the growth in a particular area. Look at what direction it's headed in and buy a couple of miles outside of that. You want the market to be heating up around your development in about 18-30 months, so your development, if multifamily, is online with A-Class brand new inventory that may not otherwise exist in that area, as it's heating up. If you buy in already hot areas, then the land costs go up exponentially and your construction budget really needs to be tightly managed. Contingency costs become even more costly.
Check your local department of buildings to see what other project permits have been filed lately and where they are located in relation to where you're looking to develop.
These are obviously all generalities and every project has it's own variables that sway the decision to develop based on asset class, size, location, etc., etc.
It's an awesome undertaking and I wish you the best of luck with it!