Wait until the first city you have is near fully grown and you have a good lay of the land! knowing how far you are from your rivals can make a BIG difference.
Culture bombs only work within a one panel distance from the border. Study how fast your rivals are growing.
This game gives a lot of leniency when it comes to placing cities though, keep in mind even CPU players build in the dumbest places and can get by alright to a certain extent.
Only build roads to connect your cities so you can get a production boost.
You could also try building on a one tile island if you must as the vanilla game forbids you to disembark directly on to a city. WARNING! Never start a game with the embark ability researched as your founding city can never be destroyed, and your one tile island city can never be captured! this means that the game could be come infinite if 2 players did this. I don't know if this has been patched yet or not.
You have to plan ahead, but you also got to play it by ear at times too. Remember the CPU players seem dumb, and in many cases they are, and the game was designed with them in mind!
Experiment to see what works for yourself! Building cities close together can allow multiple cites to attack invaders and allow you to turtle, but it comes at a price of reduced growth.. Larger cities that are farther apart can allow you to have better growth, but you end up lacking the ability to defend, striking a balance also works! It also can depend on which map size you are on.
Having lots of cities can make unhappiness, but their are ways to deal with that! On the plus side, you can produce a lot of units at once if you are at war with more cities.
Well, try it yourself and see! Just be creative and make sure you can beat the computer before you go online, so you don't embarrass yourself! That is what offline mode is for!!