It's called experience......

But generally, I start them out with bottom of wire lock & place it in the groove around 5 O'clock position, & work my way counterclockwise pressing it in with a large flat blade screw driver, mainly putting alot of downward pressure on the lock around the 12-1 O'clock position. Once you do a few, they are fairly easy. Everything I have made custom now has wire locks in it, as they are superior to a sprio-lock, hence why Cup engines have them in.