How might an instruction manual designed for troubleshooting differ from an instruction booklet designed for improving performance in a skill?

I don't know that they should be different.

The fonts chosen should be clear and easy to read. I'd use a sans serif font for chapter and section headings and a serif font for the text of paragraphs and instructions.

Any illustrations also need to be crystal clear and easy to understand.

http://en.wikipedia.org/wiki/Sans-serif

and
http://en.wikipedia.org/wiki/Serif_font

An instruction manual designed for troubleshooting and an instruction booklet designed for improving performance in a skill have distinct differences in terms of their overall purpose, content, and structure. Here's a breakdown of how these two types of instruction materials might differ:

1. Purpose:
- Troubleshooting Manual: This type of instruction manual primarily aims to help users identify and resolve technical issues or problems. It focuses on diagnosing and rectifying errors or malfunctions.
- Skill Improvement Booklet: In contrast, an instruction booklet designed to improve performance in a skill typically focuses on enhancing proficiency, mastering techniques, and achieving better results in a specific skill or activity.

2. Content:
- Troubleshooting Manual: The content of a troubleshooting manual typically includes step-by-step instructions for identifying potential problems, common errors, and guidance on how to resolve technical issues. It may also include visual aids like diagrams, charts, or troubleshooting flowcharts.
- Skill Improvement Booklet: Conversely, an instruction booklet aimed at improving performance in a skill will typically contain comprehensive guidance on techniques, strategies, and exercises to enhance proficiency. It may provide tips, examples, practice exercises, and even case studies to demonstrate effective skill development.

3. Structure:
- Troubleshooting Manual: A troubleshooting manual generally follows a problem-oriented structure, starting with a clear identification of the problem, followed by a systematic breakdown of potential causes and the corresponding solutions. It often includes a troubleshooting section or an index of common issues for quick reference.
- Skill Improvement Booklet: On the other hand, an instruction booklet for improving performance in a skill tends to have a progressive structure. It generally starts with the basics and gradually progresses to more advanced concepts. It may be divided into chapters or sections, each focusing on different aspects of skill development.

It's important to note that these differences may not be absolute, and there can be some overlap or variations depending on the specific context or subject matter. However, the key distinction lies in the purpose, content, and structure of the instruction materials, tailored to either troubleshooting or skill improvement.