Now that you've had a little more time to celebrate your Nanowrimo victory (or any other completion), now comes the time to step back and decide your next move.If you're at a total loss on what to do with your first draft then I'd tuck it into a drawer and move onto another project for a month or more. Some space between you and the manuscript will help you better see it for its flaws when you pick it up again. It's okay for it to not be perfect. More than likely it's a long way from perfect and will require a lot of work to get to the submittable stage.
Please, please, do not type The End on a novel you wrote for NaNoWriMo and then send it off to agents and editors.
The end of your first draft is just the beginning of the journey. Writing is a challenge because the finish line for your projects are always moving. The first finish line to cross is to get the draft on paper then the line moves to edits and on and on until it's finally either published or abandoned. There's no shame in abandoining projects that aren't working or that you haven't figured out how to fix. My hard drive is a graveyard of story skeletons rotting away because I realized they were bigger messes than I thought or that they were other issues I couldn't or didn't want to tackle.
I had a project I was really excited about when I started. I wrote and edited, and edited and wrote and then sent it off. By the time I started getting feedback I realized the entire novel had been told from the wrong point of view and I needed to rewrite it from the ground up. I knew I didn't have enough enthusiasm for this particular project to do it so I abandoned it. I hope one day I'll come back to it but that day isn't anytime soon. On the other hand I had another project that I wrote and edited, edited and wrote, then changed the point of view, added a secondary point of view and rewrote almost from the ground up. I still had excitement and enthusiasm for the project so I stuck with it. For me, it came down to how I felt about the project. Though you have to understand sometimes deadlines don't allow you to just walk away from a project so your experiences may differ.
So now that you've finished your shiny new draft, what should you do?
Seriously, leave it alone for at least a week and then come back to it. It won't feel like your darling baby after some separation and you can better identify the problems.
2. Read the whole thing.
Read the whole thing from beginning to end. Don't stop to fix that comma or typo. You can take notes on big problems if you want to but the important thing is to read from start to finish and see what works and what doesn't. You may be surprised.
3. Game plan.
Start with the big things. If you need to change a major part of the plot or some major character than you need to do that from the start. Deal with content problems first then worry about grammar.
4. Second opinion.
Once you've done everything you can think of find someone else to read it. I find it's best to have readers and writers look over it. Other writers will notice different things than people who are just readers. Together they can give you a big screen picture of what's working and what's flopping like a dead fish.
5. Eat a cupcake.
Seriously, find some way to celebrate and enjoy completing your work. It's easy to get caught up in what you should be doing and never celebrate your actual wins. Celebrate with a cupcake, a bubble bath, a netflix marathon or that new video game. You deserve it.
When feedback starts coming back in, rinse and repeat these 5 steps until you've got a bouncy bundle of a manuscript on your hands!