A few things to remember when improving your grammar.

Comparisons With Like & As

Use like in front of a noun or pronoun.
It was like his old car.

Use as in front of a clause which has a subject and a verb.
As in..., as if..., as usual..., as before...

Double Negatives

Using double negatives actually makes the sentence positive.
he didn't have nothing = he did have something

Split Infinitives

As any Star Trek fan will tell you, to boldy go is poor grammar.
to go boldly, to think quickly, to type slowly

To Be Or Not To Be

Be careful with the correct form of to be.
You were, not you was.

Was/Were & Should/Would

In formal language you use were instead of was.
I wish I were, rather than I wish I was.

Use should instead of would when the subject is I or we.
If I were you, I should stay at home.