There are many different conferences and workshops. Shop around, browse and choose the one for you. Work shops and conferences are invaluable to promote yourself and your work. Solid research and word of mouth, could be enough help you to decide.
Find out about the location city, who's attending and the history of the event. Are publishers and agents going to attend? If so, get acquainted. Offer to buy him/her a drink. if one of your favorite publishers happen to be there and happen to have a booth, get an issue of what she/he is presenting and have it autographed. Offer to sit at the table while he/she goes to the bathroom or goes to lunch. In the long run you will be remembered by your generosity.
Talk to everyone, not just the other authors. You never know who might be an agent and you stand a chance to elevate yourself into a good contract.
Bring promotional materials: bookmarks, postcards and magnets are great. Chapter books and excerpts are standard.
Writing is a solitary profession. Being around other authors, agents and publishers who understand and share a passion for what you do is very rewarding.
Whatever your genre, conferences and workshops help you to tell your story and find the best ways to tell them.