Slowly getting better at giving compliments

I think I'm getting better at giving compliments, at least to some degree.

While at the first store I went to, I was a bit too nervous to compliment someone's shoes (they had some cool boots with roses on them), but I was able to compliment someone else's bag while on my way home from Dollar Tree (they had a messenger bag full of pins and keychains).

I think I have an easier time complimenting people when they have something I like or have myself. Like, I remember complimenting someone because they had a Pink Floyd tattoo and someone else because they had a Pokemon keychain.

Anyone know anything that could help with building up a bit more courage to compliment people?