DO you story boarding before starting your work or directly start from software? Have you found story boarding useful?

Storyboarding is working like business plan to organize the design process and insure the quality standards. you have to use storyboard with linear/non-linear designs. you can use it withing motion designs or interactive design because both of them require a sequence of progress.

Besides Planning advantages and Organizing your workflow; Story boarding will help you get into a common understanding with the client and get a preliminary approval for your upcoming work, cause getting an approval for your story board would mean you don't have to worry about a change in a Fundamental part of you design which can be quite frustrating when working on a big piece of motion design.

Absolutely MUST! I use it to lock the scene shots that ideally should get you sense of the flow. IMO, Many people are intimidated with the idea of drawing that may not be impressive hence, they avoid planning. These never need to be awesome initially, they can be your guide. Depending on budget and time and amount of resource usually they are handled by art directors. 

If your artist working with smaller studios yes, you can use tools like Photoshop+Wacom aside from pencil and paper. Besides, PS now has basic video functionality to draw and assess the timing of each shots.

Stick figures are acceptable. If your starting out...tip.