Unfortunately, you're still competing with far too many people. You have to cut the odds. An agent loves to read, but has the time to read only a small fraction of the books he or she would like to check. Don't send an unsolicited manuscript. It will seldom be read.
Agents receive hundreds and thousands of unsolicited manuscripts, as well as a few requested ones.
If the unsolicited manuscripts are ever read, they're read last. Your can rise to the top of the slush pile very simply. You must know the process and use it. Agents don't have time to read thousands of manuscripts, so they must find ways to choose the few they can read. They expect to do this via query letters.