I started making sigs like 5 years ago (atleast I think its been that long) and I just kinda figured out how to get that "pop" affect on a sig. The biggest thing for me was the layers I put on, I used to just throw a layer on and choose one of the layer setting that worked best (ie, darken, overlay, soft light etx.). I realized that wasnt really the way to go (for me anyways), after getting a super dope texture pack from @boubabi I started learning how to make sigs a completely different way. I would suggest trying to download this texture pack and go from there.
Also for the pop affect you want to play around with exposure layers, blurring and brightness/contrast layers.