writing workshops, bootcamps, retreats
1. If you consider yourself a beginner at the writing of fiction, a classroom is usually the best place to start. Most community colleges offer introductions to creative writing, and they are usually not very expensive. The quality of the instruction will vary widely, though, so a couple of things to remember: (a) an introductory workshop is just that; you aren't going to leave it with a perfect story or novel under your belt; (b) a good instructor will emphasize the importance of giving and accepting constructive criticism; (c) the best thing to come out of such workshops is often making connections to others in your community who are in the same position, and looking for a network of people to work with.
2. If you don't consider yourself a beginner, but know of an excellent local teacher, take the course anyway. It never hurts to review basics, and a good teacher will make a difference in the way you approach your work.
3. There are a lot of short-term workshops and seminars out there, many of them in beautiful locations. Should you go spend two weeks in Hawaii or Montana or Ireland at a seminar? This is a loaded question, and I'm going to get some people angry at me, but here's my honest opinion: you go someplace beautiful for vacation; you can write anywhere. Why try to combine the two? One (or both) goals are likely to fall short of your expectations.
4. When it comes to picking a workshop or seminar, the problem is that you may recognize the names of the instructors, but you won't have any idea about those people as teachers. Good writers are often pretty lousy at teaching. There are some excellent writing teachers who have never had any real success with their own work. So how do you pick a workshop, if you can't depend on a big name? If you want to spend your money and time wisely, you'll have to do a lot of research. See where else the person has taught, and find people who can give you information on their experiences in that person's class or seminar. Ask if there are any syllabi or course materials or reading lists available to prospective students. The internet is a good place to look for information.
5. At their worst, workshops are seething cauldrons of insecure bullies set on beating each other bloody. Many are so competitive and have such an entrenched caste system that you'll feel as though you've landed in some alternate universe version of The Apprentice. Teachers are isolated from the students, and the dining room becomes strangely reminiscent of high school dramas best forgotten. If you're interested in genre fiction, you won't find a lot of support at these kinds of conferences. However. There are some much easier going, student oriented conferences and workshops -- and again, the only way to find them is to do the research and ask questions.
6. I personally get much more out of a retreat than a conference. A quiet place to work, where nobody is going to knock on the door and I don't have to think about cooking (for myself or anybody else), cleaning, errands -- that appeals to me a great deal, in part because I had a good experience at such a place. When I won the PEN/Hemingway award for Homestead, part of the deal was a month at the Ucross Foundation 
in Wyoming. This was about five years ago now. I was nervous about it, but I loaded up the car and off I went. Ucross is a great place for a retreat. It's on the high plains of Wyoming, very isolated. They give you a nice room and a workspace you have entirely to yourself, in my case a large room with a couch, a couple of comfortable chairs, two desks, bookshelves, and windows on three sides. Meals were served in a nearby building -- you helped yourself to breakfast; lunch was left outside your studio door; and a chef prepared a dinner that all the residents ate together. Lots of food, excellent quality, and most of all, you didn't have to worry about shopping or cooking. I got so much written in that month, it was astounding.
Unfortunately, Ucross is one of the most competitive of all the writers' and artists' retreats, and these days I'm not likely to get in, as they are not so very inclined toward genre writers. And then there's the matter of the puppy boys, who wouldn't be welcome, and really, I couldn't leave them for a month. Husband, daughter: sure. I can talk to them on the telephone and by email, but puppy boys just don't understand when I'm gone. Maybe someday I'll find the perfect retreat for all of us.
I can hear you asking if I've ever taught at workshops and conferences, and the answer is: yes, once in a while. Mostly I have felt that I couldn't meet my own expectations in those situations, and really, how could anybody? You end up in a small room with twenty or thirty strangers; you have no idea about their interests or abilities, and you've got two hours to make a difference to them. I try, but I never come away feeling very successful. The kind of workshop that might work, though I've never been in this situation, is the intensive one-week kind, where ten or so students work with one teacher for the whole period. For those who really want this experience, that would be my highest recommendation.