One of the most confusing usages on the GMAT is choose between as vs like.
As per the GMAT, LIKE is used to compare only nouns.(i.e. use like to say two things are similar, and let the clause that follows tell how they are similar). Like cannot be used to introduce list of examples.
The earth, like other planets, spins on an axis.
Like other planets, the earth spins on an axis.
As is used to compare clauses. (i.e. use as if two actions are similar)
A globe spins around an axis, as does the Earth itself.
Here a few of rules generally one would help narrow down the correct answer
1) Like is used to make comparisons between two nouns - make sure the nouns are close ( touching ) each other.
2) As is used to compare two verbs. As is also used to introduce list usage : such as,
3) Mostly GMAT would tend to use Like at the start of the sentence, it would be difficult use like in the latter part of the sentence without making some of the obvious errors
Try out : http://www.gmatxchange.com/tag/sentence-correction