I felt really bad about my needle skills too. I started in an ER and let me tell you, the techs were NOT subtle or gentle in letting me know that my skills were sub-par.
At first I got maybe 20% of my attempts. Now, 8 weeks of practice later, I notice I can get all the easy ones and a surprise moderate one now and again. Eventually I hope to be able to get 75% of my attempts. It is just getting the feel of it and building the muscle memory.
One of my first mistakes was not laying out all my supplies in the order I'd need them, all ready to go: INT flushed and ready, tegaderm peeled and waiting, blood tubes standing by, gauze and tape ready. Once I knew exactly where to reach for my supplies once I got that flash, I was better able to concentrate on getting that vein