as for tile sets, i personally like HG/SS the best (insurgence influenced this)
also, try to make the map look natural ish one of my biggest pet peeves is when some landmass, which is intended to look natural, looks waaay too straight (terajuma shore in rejuv, no offence to jan, but its too godamm unnatural) soo, i reccomend to make the map of your game look natural, with curves and stuff~
just my 2cents in!
also if its ready in the future, can i beta/alpha test it?