I started up more than 30 companies across 21 years. In some years I started a few, but later years there are lesser.
Disregards I am a management consultant, just from my personal experience as an entrepreneur, my little thoughts should give some helps to you. You are asking for "how" ... there are many avenues, and properly tons of books, article outside there you already read.
Can we look at "what" and "why" you want to start a Salesforce consulting company? If you ask me given 10 hours for me to do a strategic task, I will spend 6-7 hours to do understanding, 2-3 hours to plan, 1 hour to execute the task. Therefore I am so into "what" and "why" at start.
1. what you do or intend to do?
2. got sufficient people to buy or not? already there or need to find?
3. what you want to achieve = volume, value, duration?
4. so on
Many questions on the "what" and "why", please do more in depth on these before you look at how. Once you have thorough understanding of "what" and "why", you somehow will be guided to "how" very easily.
Hope the above help you to kick-start. Drop me any message if you still cannot obtain that level of clarity to push you forward,