Time spent with it is your best friend.
The more you do it the better you will get at it .catching roaming fish is a blast but that takes getting accurate with your cast
And lining things up to be able to see your bait and the fish. I do a lot of scanning with the scope with the trolling motor on fairly high speed to cover lots of water sweeping the live scope as I go along until I find structure or a fish then I slow down and investigate it. I keep my range set at 50’ and on a new lake I start out going down the bank about 40’ off of the actual shore line that way I’m scanning about 90’ as I travel. I have read/seen a lot about what keeper fish look like but that’s no always the case unless mine isn’t set up right I have caught fish that didn’t look a whole lot bigger than my bait and it be a 12’ fish . As said most crappie that you find with be just setting their and not making much movement if you see lots of movement prolly not crappie unless they are chasing bait or moving school.