Scenecore is usually associated with glam punk. It's following music trends and applying fashion trends to them, and those fashion trends are usually as mainstream as it can be in the punk scene...and they are considered to be posers too. It's also dressing just to impress rather than just wearing something that's cheap and comfortable.
Boys usually wear tight shirts, girls pants, and sometimes "emo" style hair
Girls usually have short hair, sometimes with really short bangs, pin straight, dyed lots of times
bandanas around the ankle and wrist is scenecore, and so are really huge sunglasses and small hairclips.
It also seems like a lot of scenecore girls go to shows just to meet guys, and vice versa.
Ohh man look at that girl...
she looks like she just went on a shopping spree at A&F and thrift stores...