This is just an example of my build. I do buy different items occasionally due to whom I am laning against and other things. Some of those things to consider are what your creep score is, if you are up against the opposing laner then definitely go for this build since you are up BUT if you are down in creeps (meaning down by more then 10-15 creeps) I would try to get some different items suck as instead of saving for a sheen maybe get a sapphire crystal to catch up on your gold.

You may say "Why would anybody take ignite of Brand when he has a built in ignite?" Well to answer the confusion I take ignite because of the masteries I chose. One of my masteries makes me do more AP damage and AD damage while ignite is on cool down. As simple as that. Now if you did not take that mastery then I would not suggest taking ignite and I would suggest taking barrier or teleport. I chose flash as my other spell because well it's flash and flash can be the difference between surviving and dying, or it could be the difference between you getting that kill you really needed or letting them get away.