I have two one beds in Class A Bk neighborhoods, and they have not been easy to rent out lately, yes the market is rapidly improving, but it could still take some time to get the units filled, so I would be hesitant to pursue a deal where the margins are so tight. 

Which all key figures help developers decide on negotiating terms of JV for development(build and sell).Deal here with one of Landlord is, 52k sq ft plot, Multi Use development possible (Ground + 1 floor parking, 4 floors of commercial space, 14 floors of residential apartments).Owner is not ready to give up on 55 - 45% JV model (55% for Developer, 45% for Land owner + 1.2 mn USD cash).Where as out of 4 prospective Developers, no one is ready to be beyond 34%.

Thats how this REI business works, you learn from someone, then its your turn to help someone younger.Don't be tight fisted about paying for education, boot camps etc. 

The cost is going to be less than 30k because I will build it myself but obviously the county won't just accept my "random" estimate, they will allow to estimate $123/SF of conditioned space and $22/SF of deck.The floor plan I was planning on building is coming at $37,404 (288 SF floor plan, 90 SF front deck), so my question is : shall I make it smaller to get below that 30k limit ?

This is huge for you as a new person in the space to do it repeatedly and learn from someone that has massive experience. 

But in 1-4 door space and Fin of Am you can get 30 yr am fixed term. 

We offer it to free for our clients because we know that it seals the deal when people walk through the space.   

Larger square footage may also be dividable in a way to create multiple living spaces.

Pick up trash, clean ac condenser coils, check all cabinet pulls for tightness, lubricate door hinges and make sure security devices work properly.

Start with a small insignificant space to learn what you need to learn (keeping planks from shifting, layouts & cuts, etc).