you don't. at least not in a formulaic sense. there's no "guaranteed way to go viral" stuff on the internet just kinda happens and you roll with it
like i'm not someone who's mega active on tiktok. i posted one video as a joke it managed to get a pretty decent amount of traction and then i moved on with my life.
so if anything a better question would be what performs well in terms of content, framing and presentation and to figure that out requires exploring the areas of tiktok you want to advertise to be it gaming or music or anime and so on and so forth
like again there's really no exact formula to having a post blow up but you can at least figure out what works in terms of getting more eyes on your content on these platforms because at the end of the day nothing is promised and most of these platforms are designed against us rather than in our favor so that we keep feeding them content in the rare hope that maybe possibly one of our posts might go viral and explode so like do what you can but don't stress if things aren't turning up with huge numbers (depending on what you consider to be "huge")
as for your editor guy's rates on fivver i know that the site tends to have folks offering work at perceivably lower costs but sometimes it has to due with geographic location and then that specific country's currency and exchange rates. i can't elaborate well enough on that since i'm in the stinky stars and stripes country but hopefully someone else could elaborate better