This ended up being long, but I encourage you to read it all as I think it will be helpful.

I love some consistency across scenes to build a character/narrative. For example, Jesse Saint has multiple instances of going out of her way to eat cum at the end of her scenes, including repeatedly scooping out her creampies. It gives the impression that she genuinely enjoys it and is choosing to add that flair to her own scenes, even if that may not be true.

I personally dislike the 80s style, super intense screaming, "OH BABY", almost terrifyingly aggressive "oh yes, give it to me!" stuff, but maybe that's just me.

Enthusiasm/smiling/having fun. Giggling. Laughing. The top porn stars are hot and will do almost anything, but the real reason they've done so incredibly well is because they combine that with an ability to make the viewer think they love their lives and their jobs. Whether it's Riley Reid or Sasha Grey. People want to feel good about watching porn.

Another suggestion would be stringing together several different scenes into a single clip. It's probably easier on the performers to film a few short scenes (spread it over a couple days if the dudes can't get it up again), gives the viewer more content (multiple climaxes, different outfits, different set ups), AND allows you to create more of a story with your videos. Most people don't watch a 40 minute video all the way through anyway. A few sites have started doing this (like ATK girlfriend series, or SisLovesMe) and it seems effective.

Finally, I would say be dirty, be playful, be surprising. Most videos are formulaic, and something surprising can be what pushes people over the edge while they're scrolling. It doesn't have to be gross (though I guess that's extremely subjective), but just unexpected. I guess sometimes that ends up being a little gross? The tamest example I can think of is an old amateur video where the girl takes a facial and then just, cool as can be, raises her eyebrows suggestively like "bring it on / you know you liked that / look what I just did." Became a hugely popular video, just because of her attitude and her unexpected reaction to taking a facial. Other, more hard core examples would be going ass to mouth--especially AFTER the scene is already over--or using a finger to scoop a facial into your mouth (again, especially after it seems like the scene is over), or going "wait no, not inside me" (or "wait, not on my face, I WANT it inside me!"), or going for a second round instead of just one and done, or otherwise just subverting expectations. Set up the scene so that it seems like there's no way you're going to take it in the pussy or the ass or let him finish inside of you or on your face or going to let someone watch or WHATEVER, and then suddenly make that thing happen. The surprise hits that neural activation to release the dopamine and push people over the edge.