Let the students know at the beginning what you will be teaching and how much they should already know. Tell the students if the workshop is for beginners or advanced students.
Provide a computer for each student. Install the needed software on each computer. Computer students expect to practice what you are teaching.
Teach only one topic per workshop. Students need time to learn and then try the new information they have learned.
Use a projector hooked up to your computer so that you can demonstrate on a large screen as you go through the steps.
Make sure the lesson is hands on for kinesthetic learners who learn by doing. Allow plenty of time for students to try the software and the lesson.
Provide handouts so students can reread the lessons at home later. Write your lessons in detail, step by step, so the students can follow your directions without you there.
Keep it simple. Remember you are an expert but your students are not so don't use complicated computer language that they won't understand.