Publishing is a tough business. It's rewarding, to be sure, but the hours are long and the revenues are miniscule. But if you have the fire in the belly to help the next generation of literary talent find its voice — wonderful!
Write often. Study the craft. Avoid vanity presses. Build a platform. Read the guidelines. Find a writing group. THEN, celebrate success.
Think carefully about the pros and cons of engaging in multiple and simultaneous submissions. Acceptance barriers aren't always someone else's fault.
If you can position your work solidly within a constellation of known sellers, you’ll more easily convince a hesitant agent to advance your manuscript.