As other people have said, a signature sound will emerge naturally, by the aesthetic and compositional choices you make.
To try and create one or strive to have one is very counter-productive and limiting. I've heard beginning musicians or producers say this kind of stuff, and it just inhibits their artistic development. Learn your trade/craft first.

Presets are totally irrelevant. I remember this psytrance band I liked back when I was into that kind of music, a friend of mine had a virus and nordlead, turns out most sounds were stock out of the box presets. But they rocked it, and were totally original.

I do try to make music within the same concept, similar to stuff I like, usually quite dark (although when I create more complex sounds they tend to be rather OTT and get almost gaudy/cheesy. Then the trick is to tone them down or use context/arrangement to take off the edge of the erm 'christmas?' vibe.
My one rule of thumb is, I don't like sounds that sound too 'synthesizery'
I break that rule constantly.

I was working on a track with a specific sound and vibe on mind recently, got totally stuck with it, nothing seemed good enough, or enough like what I was going for.
Decided the next day to do a palate cleanser, just make a fun song without expectation or intent. Almost purposefully tried to do something totally outside of my 'sound' it could even be a happy hardcore or cheesy disco tune. Fun&games.
Ended up with a great track, that actually has my 'sound' more than ever, without a forced angle and therefore a lot more original.