Not in any particular order, but here you go:
1. Not everything is ready to be published.
I wrote and self-published four books when I was in high school. I was self-publishing before it became a trend, lol. As a young writer, I didn't really understand the true value of many drafts, revision, and editing. I've learned that it is important to push yourself and stretch your creativity, but not everything you write is going to be a bestseller let alone worthy of literary representation. Choose a project you feel passionately about and give it the TLC it deserves. It's important to know when to move on, but it's also important to know when to stick to it. There is no formula for this. It comes from within. I started Picking up the Pieces (now Podium Finish) in 2006. I self-published it in 2008. I thought it was done and I tried to move on. I've written other things, and completed college as a student athlete with A's in the process, but no matter what I did, I knew PUTP could be better, so I went through revision spurts. The manuscript today is a thousand times better than it was and is COMPLETELY different. Moral of the story: don't give up on a project you love. Other moral of the story: the other things I've written in the past few years are not ready to pitch. Four years ago, I would have self-published. Self-publishing isn't a bad thing, but I've since learned that if I wouldn't feel comfortable pitching it, it is not ready to self-publish by my standards.
2. Good ideas take time.
I have been working on PF off and on for 6 years. I'm 22. You do the math. Obviously, not all books take this long, but I've learned a great deal about my strengths and weaknesses as a writer along the way and this will be useful information when I start my next project (AKA my grad thesis, a middle grade novel.)
3. Get beta readers.
Get beta readers or critique partners. These can be people in your workshop. It can be fellow writers you meet on line. Basically, find someone who is able to critique your work objective. Obviously friends and family can be helpful, but remember they're friends and family.
4. Find the bright side in critiques.
Being told "you have an excellent writing style, but I'm not connecting to the voice" sucks, but that person is telling you a strength and a weakness. Know what you do well and know what you need to work on. Don't beat yourself up at the rejection. Confidence waxes and wanes, but don't let it break you. Find the silver lining.
5. Query strategically.
This can be anything from putting the genre in the subject line like: Query (YA Contemporary) to FOLLOWING submission guidelines. Do your research. Agents will usually say on their websites whether or not they want sample pages and whether those sample pages should be attached or embedded in the body of the email. Don't stand out because you were the one who didn't follow directions. Also, send out 5-8 queries and wait for a response. This will tell you if you have a strong query letter. Also set up an excel spreadsheet that tracks who you queried, when, and the response. There are lots of agents out there and sometimes the query process can be overwhelming. A spreadsheet is useful and free.
My writing has greatly improved since I started reading more. I read mostly YA because that is what I write, but make sure to read a variety. I don't write dystopian, but I've read several that I like and have learned something from. (Divergent, Legend, The Hunger Games) These books have action and emotion which can be universal. I write YA sports fiction/YA contemporary. Action and emotion are important in that genre too. I write action well, but struggle with capturing emotion. Reading how published writers handle it has helped my writing. Reading YA Contemporary has also helped when I write YA boyfriend/girlfriend relationship scenes.
7. Stay connected.
There are several great blogs with reviews and writing tips. There are also lots of giveaways and contests, so stay connected to the writing community. I entered GUTGAA and won a 30 page critique. That person has since read more of my work. I also won a $10 amazon gift card (which I used to buy a book on Kindle and an episode of Homeland--just got hooked on that show.)
8. MFA's are great, but not necessary.
I just completed my first semester of grad school. I met some wonderful friends, and I know I will miss the workshops while I'm in South Africa. (I also know I'll be doing some pretty amazing things in SA.) I wish I had applied to more grad schools. I don't know that I would have gone to a different school because UBC was my top choice, but I have recently found other schools with strong programs that I hadn't heard of and wish I had. I thought I needed to go to grad school. One because I had such a strong academic background, it was something I expected of myself and thought others expected of me. Two, I didn't think I would do well with a gap year. I now realize that I would have done fine if I hadn't gone straight to grad school. I was actually the youngest in the program--one of three 22-year-olds. That being said, I think I made the right choice. I also know I don't need an MFA to be a good writer. It's something I'm doing for me.
9. Use dropbox.
It's a lifesaver.
10. Upload your book to kindle and listen to it when editing.
I already posted about this so I won't say too much more, but I did an edit then upload my manuscript to kindle and had it read to me. I caught typos that I had missed. Me instead of my. Of instead of off. Dropped words. Extra words. Having it read aloud helped so much.