I'm here but only briefly. I'm on my way to my crit partner's house. We luckily live close enough that we can get together from time to time and hash things over in person. She's not the only person I run my writing through, though. As part of ANWA I participate in a monthly meeting with writers in my area, helping each other along this path.
If you don't feel ready to sit in a room and be critiqued, find an online group to join. For several years I did Critique Circle. It's actually a great resource for getting back unbiased critiques. And it helps train you to see what you miss when you edit yourself. It's totally free, the only thing you have to do is give critiques yourself, which is also excellent practice.
Why am I telling you this? Because you have to do it. You have to send your work out into the safe world of a crit group before you should even consider sending it to an agent or publisher. And they will tell you this, agents and publishers will. Back in the day, a publisher took the author under their wing and nurtured their writing and their growth. No more. The golden days of publishing are long gone. In today's world, your work needs to be a shiny, sparkling, almost flawless diamond in the hand of an agent, one that can stand up to the jeweler's examination.
So when you've gotten your work as clean as you can, before you send it to anyone in the biz, send it to a writer friend who you can trust. Take it to a local meeting. And if you don't have one, create one. Or use one of the myriad of online resources to continue the buffing and polishing process. Because the agent or publisher needs to be able to see themselves in your book--they need to see that you are already a part of them so they'll take you on.