What advice can you give to somebody who’s thinking about starting to write TF stories?

Well, you can start by reading the entries in my metawriting tag, for starters, unless you have already. Beyond that, it helps to start by copying the style of stories you like. Most of my early stories were just poor facsimiles of stories by Onix and Peircedskin. But more than anything, you need to actually sit down and write the damn story–that’s the hardest part, and it will always be the hardest part.