I applied through college or university. The process took 1 day. I interviewed at Virginia Tech in Dec 2014
Interview
I needed funding to continue with my PhD studies, so applied for it. Was hired because senior graduate student and had required qualification for the course. Plus funding constraints. No negotiations are required. Its a fixed salary, same for everybody. The experience is pretty good, plus you learn a lot about the teaching methodology and course material. Its worth doing atleast one graduate teaching assistant in your student carrier. Undergrad TA can also be useful.
I applied in-person. The process took 4 weeks. I interviewed at Virginia Tech (Virginia Beach, VA) in Dec 2018
Interview
Based on GPA and studies in undergraduate program. They might consider the TOEFL/IELTS and GRE score at the start. Depends on the the hiring team, also the prefessors recommendations might help. But cannot assure.
Interview questions [1]
Question 1
What courses you have undertaken and what marks did you obtain?
It depends on the department you are working with.It could be really hard or too easy. For me it was really easy to get in but kinda hard to survive. But i Loved it