I don't think "most" longarmers are computerized, though it is becoming more and more common. I do only hand guided work on my longarm, not using pantographs or computerization. Most instructors stress the importance of doodling your design on paper before starting on the quilt. That helps to get the design fixed in your mind, and you get to practice covering the whole page evenly. Mixing a few different designs (e.g. swirls and pebbles) gives the quilt more interest, and also helps fill in holes. The other trick is to do a lot of echoing.