Prior Planning and Preparation Prevents P*** Poor Performance.
The more prepared you are the better. Know all about your initial and branch training, flying hours, aircraft, streams of WSOp and what aircraft you'll be flying in. If you speak like you type then you may be knocked for poor oral comms.
Don't litter your sentences with umm, err, like, you know and obviously. Don't say wiv instead of with, I done instead of I did, we was instead of we were etc etc. Poor oral grammar and fluency is the bane of the AFCO Filter Interviewers life and OASC!