rough in plumbing plan??

ok...have stem wall in..(im in florida)..i have to now do my rough in plumbing...been trying to figure out the best way to do all this, one question, is it better to run my inch water line, under the slab, then run my fixture lines from there up and through joists and down walls to the fixtures? or run the individual lines under the slab??...is there a good place to look at the proper way to design my waste water lines?....thanks for the help..
rick

...im using pex for the water lines....looking for ideas on the best way to run my drain lines...thanks for ANY input...i do have a working knowledge of plumbing, and have done my share of plumbing work (laundromat owner, father was a plumber..etc..)....thanks again....

Other than telling you the obvious (slope it downhill) it's pretty tough to offer help without knowing the plans, and if the plans are already drawn, what's to tell?