Get access to your home institution cath films. Attempt to read them yourself, then follow up with the final read. If you have questions, ask the advanced fellow and/or attending why they read something as such.
I've noticed that a lot of attendings will read films to obtain some goal- ie get the patient to CABG (sure that LAD looks like an 70%).
Get used to the views. Understand what views display what vessels well and which part of vessels well. Understand if there's overlap, how to change angulation to get what you want.