There are 47,936 members on Query Tracker and 688 success stories. That's 1 in 70. Since members of QT are arguably better informed and motivated than average the odds of a given writer finding a decent agent is probably more like 1 in 100 or worse.
Think about it. You have to run a race against 100 other people and beat them. Being 'good' is not good enough. At least 10 of those 100 are 'good' writers.
So, sit down and think about high concept (read up on it if you're unsure what exactly it means). Think about what's been done in your genre and where there are gaps. Then you need to write a book that fits comfortably in your genre, yet stands completely apart from all the others next to it on a bookstore shelf.
Then do an awesome job of plotting, writing, editing, finding good beta readers, editing again, picking apart your weaknesses as a writer, editing again, finding more good beta readers, editing again and then give it one more go, just for fun.
If you followed all the steps and you're a good writer you'll get an agent. 90% of your competition does not know what it TAKES so you can write them off. Learn what it takes to sell, and I mean REALLY learn. Then you're in the top 10%, do an awesome job of writing, that takes you to the top 5% or so. Keep at it and you'll get there.