leveling then evolving rather than evolving then leveling doesn't make any difference in my experience.
I think it's best to collect as many as possible. Then evolve the ones that are already high cp. This will give you a decent amount of high cp pokemon. Then if you really want, spend your stardust on bumping up your fav's (ie. don't waste your stardust)
but i wouldn't spend the stardust until your at >level 18
yep, but evolving seems to be the best way to level
If you're in an area that spawns load of low cost evolving pokemon, then it's a good idea to catch and evolve as many of these as you can for the level boost. We get loads of pidgey that cost 12 to evolve, they seem easiest method of leveling.
leveling then evolving rather than evolving then leveling doesn't make any difference in my experience.
I think it's best to collect as many as possible. Then evolve the ones that are already high cp. This will give you a decent amount of high cp pokemon. Then if you really want, spend your stardust on bumping up your fav's (ie. don't waste your stardust)
but i wouldn't spend the stardust until your at >level 18