How are you painting them, with an air brush gun or spray can or paint brush? Only thing I can suggest is that you make sure the paint is put on evenly on the bait. Also, dont be afraid to try something new, get creative with how you come up with patterns or even shades of blues or red or whatever colors you are trying to “match”. I took a lipless crankbait and sanded it down and I wanted to paint it a red craw pattern, found a design I liked but to get the lines on the side were of a gold looking color, I didnt have anything that matched it, so I took a silver sharpie and drew the lines on there and then hit the bait with a candy red paint, cleared over it with a pearl clearcoat and it came out great!!! Fished it at Newton Lake over in Illinois and caught a fish on it, made me feel proud I painted something that caught a fish, keeper too. I lost that lipless crank on another trip out there though. :( Oh one other thing, if you are taking a crankbait that is already painted and you are sanding it down, be careful to not oversand on one side or the other or put dips in the bait from sanding too much in one spot, it can alter the way it runs in the water.
