well, usually i played the dark side of the pizza tycoon first, that is to become a godfather or at least a rank below godfather.. after that there won't be any annoying gangster asking for protection money and you can access the missions to earn more money.. money laundring was the easiest, quickest and least risky if you asked me.. :P just do some depositing at the nearest bank to some bank account.. i once got 300k just doing that in less than 1 minute..
now that you got money, try to find a place, either you buy it or rent it, that got the largest population around. you can see the information at the right column.. and as i said before, try to make a 'trendy' pizza and make lots of variation.. i once got about 30-40 recipes (which i made myself) and as the result i got a branch with monthly income of, roughly, 80-100k
hope this helps..
