Outline your work.
It’ll keep you on tangent. It isn’t necessary to go into everything. For the novels, I outline what has to happen in each chapter but not necessarily what leads between each scene unless I have thought of something immediately. I like a novel plan to be flexible enough to allow for ideas as you go (that should happen, as it shows your story’s “alive”) so you can fit them in but to give enough of a structure to prove (a) I have one (!) and (b) I know where the tale’s going to end up even if I don’t know the exact ending. For short stories, I outline the character and focus on one point of change (there’s generally not enough room for more given the limited word count).
Keep a copy of all you send out.
Never send precious originals (this is even more pertinent for artwork and photos). Items getting lost, postal strikes and spilled coffees happen!
Keep a record of what you send where and results.
Useful for accountancy purposes and to make sure you don’t send the same story to the same person twice (unless, of course, they’ve asked you to resubmit it, highly unlikely). Also I’ve found using the Mslexia diary helpful – for one thing I’ve been overcome with the urge to fill the blank pages and the only way to do that is to get work out there. The more work out, the greater the chances of success but it then becomes more vital to be able to track what you’ve sent where.
Read your work out loud (to yourself, a friend, a recording device)
Vital for poetry, it’s also useful for prose, particularly dialogue. If you trip over words so will your readers and then it’s time for the editing pen again!