Be prepared by knowing your material backward and forward. Workshops are usually only one class, so you won't be able to answer questions at a later date.
Talk in clear friendly manner. Watch for students who look confused. Provide time for discussion. Encourage questions as you go so that you don't lose anyone along the way.
Hand out notes so students can follow along as you speak. Many people are visual and need to read lessons on paper. Others like handouts to review at a later date. Give out a resource sheet with websites so students can find more information.
Teach to all learning styles. Give handouts for visual learners. Explain things clearly for auditory learners and show things to kinesthetic or hands on learners.
Test all equipment in the room before you teach your workshop. If you are using computers or a projector make sure everything is set up properly.
Get students involved by asking the students questions or get them to discuss topics with each other. Make the workshop interactive and fun.
Give out an email address so students can contact you later. Often when information is packed into a short time frame, students don't have a chance to think of all that they may need to know.