Keep an up-to-date copy of The Writers’ and Artists’ Handbook. Contact details do change frequently.
Don’t give up!
Research agents, publishers etc. Check details out against the Jonathan Clifford website (given he’s spent his life fighting the publishing industry’s “sharks”).
Don’t be afraid to ask questions (but do some research first so you ask sensible ones, not something that a quick look on the net would’ve told you).
Remember when writing short stories you are looking at a relatively short period of time in which your tale “happens” so focus on one character, one major change of life event and one viewpoint. You haven’t room (word count) to have too many characters, viewpoints etc.
Writing short stories and entering them for (reputable) competitions is good practice at writing to a theme and to a deadline.
Buy the magazines you would like your short stories to appear in. It is a question of supporting your own!
It really is worth double checking spellings and grammar are correct before sending anything out. You don’t want to give “silly” reasons for an agent/publisher to turn you down. The only reason should be your work is not right for them. Also there is a presumption if you can’t be bothered to check things like this the rest of your work will be littered with mistakes. Nobody has the time to correct these mistakes – it is what you as the author should do.
Read other writers’ blogs (look for those with a good record in the profession) as you learn a lot from these, including how to present a good blog! You learn a great deal by absorbing. Follow a few good blogs (if only to make sure you still have plenty of time for your own writing). If you decide to set up your own blog, plan it well before you start so you have plenty of material to “feed” it.