Hi
Well done for posting and being open to opinions as this is all about learning and progressing. Its good you haven't jumped straight on to clients as so many do after taking a 4-6 hour day course and thinking your a hair extensions expert!
Aside from the client supplying the hair (cheap looks cheap) and blondes are even harder to pull off so don't be out off. For those saying your pictures look fab...sorry but they don't. Not being mean, the clients hair quality aside, the extensions look gappy, stringy and well like extensions. They should look thick, no gaps when straight and even, with movement. These look like cheap bad extensions something it's clear you want to avoid and can.
I would recommend you start sourcing a good hair extensions supplier first, who use 0.8g strands as a minimum, thicker hair, shorter hair needs more grams so 1g strands too.
Then get that dummy head out and practice, practice, practice. You will be amazed at how much you will learn on your own from removing, reapplying 4-5 full heads.
Then try and rope in some friends, mates rates and fit their hair and give them some business cards, post their pics on facebook using your hair, get a backboard with your logo so pics look consistent, professional and worthy of your work.
It does take time to build up a clientele and its hard work but if you can do it. Good luck and hope I've not come across harsh...and just taken as honest, professional advice x