WCA highly recommends the use of Cube Comps before and during a competition. Cube Comps is an online system with live scoring and many interesting features, like scorecard printing and a very efficient multi-user data entry system. Created by Luis J. Iáñez and now under Open Source.
Score sheets and scrambles should be processed and checked for errors using the WCA Workbook Assistant before sending them to the WCA Results Team.
The latest version of the WCA competition Score sheet can be downloaded here:
WCA competition Score sheet.
You may also want to use Groupifier for preparing competitor groups for a competition. It's a tool that aims to do exactly this for you. Among the main features you will find: sorting competitors by rankings, assigning tasks (judging, scrambling), deciding how many scrambles are needed, generating scorecards, personal cards, and summaries. It's an Open Source project created by Jonatan Kłosko.