It's of vital importance to get a good economy going, in order to support your expansion. Whether you're a warmonger, taking enemy cities (or just razing money to support an expansion) or going for normal expansion, with settlers.
I find that a Financial leader helps here, especially with cities built near rivers - in order to cottage spam at riverbanks - and with one or two Commerce yielding resources nearby. My idea of a good starting position, almost for any leader or tactic, is a coastal start, with seafood in the BFC. Of course, you need Fishing for this to be of any use, but still...And then satrt out by building a Workboat or two. As opposed to Workers, the production of these do not stop your city from growing. I find that a rapid city growth (not too fast, you still need to avoid Unhappiness) gives a good start.
I also like early Unique Buildings, since almost any bonus from these is good fro the rest of the game. Hannibal of Carthago I like, Financial, good early UU and UB. Go for early Horseback Riding, and a handful of Numidian Cav will keep the barbs from your doorstep. With his Charismatic trait, they quickly become veteran units.
Are there any Fin/Imp leaders?