I think the best way to show love is to just be engaged with the person you are with. And I don't be "about to be married" engaged. I mean, take an interest in what your partner likes. For example, my husband enjoys video games. If he's playing a game that I think looks interesting, I'll sit with him and watch him play. Meanwhile, my husband has taken a few trips out to help me at my craft show tables. We both have our own separate hobbies but, at the same time, we know that it's not all about the "Me."
The same theory runs true with my daughter. Sometimes I'll sit and watch TV with her or we'll play games together. She also helps me make jewelry and helps out at my craft show tables when she can.
I don't really think that you have to be gushy with the displays of affection or anything. Just be with someone when you are with them. Put down the phone or iPad for awhile and just be together. Simple as that.