Do all your sums.
What is fun as a hobby can turn out to be an utter and complete bastard as a job.
Work out what you need to make on each item to cover the materials, the overheads AND at least some of your time.
You are not likely to be paid even min. wage for your time, thats a fact of making stuff by hand really so you need to be sure that you can price your products up so that you are making a profit on materials.
Do NOT start out by charging low prices because you are new at this etc etc.
Start out at a fair price for your product, you CAN offer things at 'new product trial rate' for a limited time only, that makes it clear to customers this is NOT the normal price, prices will go up.
If you start out stupidly low you get inundated with orders you cannot afford to complete in a reasonable time frame, then customers get pissy and start to grumble, you get stressed, hate it, folk start asking for refunds, you start wanting to hide rather than do this any more.... and so on.
If you make to order, work out what your custom options are and stick to them.
If you offer things in two fonts and three colours then yes, folk will ask you for a third font and a fourth, fifth, sixth colour, and can you do it in a style you don't offer etc etc.. stay tough.
I would NOT advise offering totally bespoke products, the time you spend going back and forth with one person changing their mind every two seconds you could have banged out 10 'standard item with 1 customisation option' that would have earned you more for less stress and effort!
Do some free courses on business and marketing and tax stuff and get GOOD at being very organised about your financial admin (take it from someone who files all her financial shit in a box labelled 'magical maths department' for the whole year then spends two weeks panicking trying to sort it out to do her tax return!).
It can be great, being paid to do something you love.
It can be an utter fuckery of disaster and turn something you love into something you despise!