If I may add my 2 cents, though you seem to have solid advice from very experienced people already.

I have ran a number of businesses in various industries over the years (gawd that makes me feel old) & found there are all types of customers out there. Some you will keep forever and some you can't run away from fast enough. Time & experience will help you differentiate the two.

As far as setting a rate goes it very much gets down to confidence. Confidence in yourself, your skill set and your ability to complete the task. You have worked HARD to gain your knowledge. And you continue to work HARD to keep it relevant and up to date. You have worked HARD doing the grunt work, working your way through the system to become the man (or woman) you are today. You have spent you hard earned cash as you progressed through the system on tools and equipment to make you more efficient in what you do. If what you do was easy then every mug would be doing it. Don't sell yourself or your hard work short!

On the business front:
It is important to acquaint yourself with reliable suppliers with a quality product who actually know what they are selling. Treat these people with the respect they deserve. When things don't go according to plan, and they will. These people will soon become your crutch & ultimately your savior.

It's a business deal, and a customer is just that. Many will comport themselves as "a friend", but this is only a ploy to get a sweeter deal. A friend is someone who's house you have been to for dinner, or gone on holidays with etc. etc. How many customers can you say you have done this with? While we're on the topic, that never works either. Friends and business truly DON'T mix.

A paying customer is entitled to a few things. Your professionalism in work, advice and manner. To be kept in the loop, this applies to delays as well as running on time updates. Respect, the person you are dealing with is more than likely just doing his/her job. They undoubtedly have someone THEY need to answer to.

Be reliable and trustworthy! If you say you're going to do then do it. If you're doubtful, then be upfront about that. If you think you can't then just say no. Failures happen (refer to Murphy's Law) but there is nothing worse than the failure you know you should have avoided.

Accept responsibility for your failures. It's hard, but trying to BS yourself away from blame makes matters worse. Accept and deal with it. You're only human after all

Never forget it's YOUR name on the finished job. That means it's your name attached to the decision to use cheaper or inferior products, or to use scotch-locks where solder joints should have been etc. From experience I can tell you a customer never says the job failed because I pushed for unreasonable deadlines or I chose to go with a cheaper product.... They simply say (insert your name) F'd up, he's sht, don't use him.

Don't be afraid of being an "overcharging learner" as you put it (within reason of course). The nature of the beast is that new things will pop up from time to time. Just try to handle it without scratching your head or that lost look on your face. Someone on this forum once had a tag that read something like "If you think you know everything you soon realize you actually know nothing". So true....

Last but not least, this is the advice I gave to a few of my apprentices when they wanted to go their own way with a new business venture. F%$K OFF YOU F*$^ING INGRATE...YOU PIECE OF Sh! Just playing. What I actually said was pick something you're good at, something you enjoy doing and work hard until you become the first name that falls from peoples lips when they think of that thing.

Sorry if I wandered off topic a little, it's just that I see you want to succeed and I want you to succeed. If I can contribute to this with my advice/experience then I am happy

You want value? How's that for stretching the absolute out of my 2 cents worth