you've written the perfect book, you've sent it to your friends and they say it's the next 'Lord of the Rings'.
You want to send it to an agent so they can find you a publisher.
One, cardinal rule before you even CONSIDER sending it to any agent.
CHECK YOUR SPELLING. Repeated spelling mistakes are really not the way to win over any agent. If I have to trawl through misspellings of commonly used words, I will give up after the 5th page and go on to someone else's manuscript, in the hope that they know how to use an english dictionary.
Same goes for grammer, actually. If you use an average of 3 commas in every sentence, no-one in the publishing industry will be impressed.
Seriously. Agents do expect basic levels of literacy.