Exclamation points tend to be overused. If you use them very often, they lose their effect. It is not necessary to use multiple exclamation points or question marks at the end of a single sentence. Sometimes this is done to add even more emphasis, but it is rarely effective. Use commas as short pauses between parts of a sentence, or to separate items in a list within a sentence.
Apostrophes are a little tricky, but worth mastering.
Be sure to use apostrophes in words that are formed from two words, where part of one of the words is skipped. For example, can't is a contraction of the words can and not where the n and o in not are skipped, and replaced with an apostrophe. If you don't use the apostrophe in the word can't it means something completely different. Apostrophes are also used when pluralizing single numbers or letters, such as 5's or R's. Apostrophes have one other very important use.