Apprenticeship openings for electricians and welders - any advice?

The training centre near Kansas City opened applications for apprenticeships in electrical and welding trades. I have read a lot of threads here and could not find my exact situation. The application needs a diploma or equivalent, a driver's licence and a short aptitude test. What do you wish you had known?

The aptitude test was mostly maths and reading a diagram. Free practice tests online were enough for me.

Visit the training centre in person if you can. Seeing the classrooms helped me decide.