You can improve Feet by either using your feet in sex (rubbing feet against pussy/penis; requires at least Promiscuity 3 to do so unless the other party is in a submissive position, which in vanilla DoL is from very specific events only), or pay 12 pounds per hour on Tuesdays and Thursday to learn how to how to do so at the Dance Studio (requires you to be wearing High Heeled shoes when you visit on those days). That said, High Heeled shoes are not necessary to do the dancing minigame at all, unless for some reason you are forced into using it - the only time Feet is used at all is if the stage is starting to be covered in semen.
To avoid getting raped in the Brothel (and in a few other instances where you dance in similar circumstances) while getting that cashmoney, you have to maintain the audience's Interest at a high level (first indicator; goes from 'distracted' to 'obsessed') while managing the audience's Arousal (second indicator; goes from 'chaste' to 'filled with carnal desire'). Both will increase the audience's Awe stat, and all three stats have an effect on the size of tips you get. One of the places where you get nothing for dancing is the Underground Brothel, which you probably were at, and is considered to be one of the Soft Bad Endings.
In any case, for dancing, the idea is to use mostly the second dance option ('sophisticated dance') while using the third and fourth options sparingly ('sexy/sexual dance'). If all you're doing is nothing but sexy/sexual dance, you'll max out audience Arousal in an instant and they'll descend onto you. Sophisticated dance maintains the audience Interest while dropping their Arousal, though if you need to drop their Arousal fast, there is the first dance option (which while drops their Arousal the most, also drops Interest). You also want to be dancing in front of different audience members, mainly the ones at lowest risk of orgasming, especially if you're going to do a sexy/sexual dance. Having an audience member orgasm while you're dancing in front of them increases Arousal more and make them more likely to try certain actions like pulling your clothes off.
As for increasing Seduction level, there are a few ways you can do this. One of the 'safe' ways of doing it is to do it in the School Library every day when the Math Competition is ongoing - once a day, there will be someone working on their Math Competition problem that you can try to distract for a Math Insight. Another 'safe' way is when you've worked at the Dog Pound enough that Pound Respect is high enough that you can 'Walk the dogs' - for some reason if you choose to struggle to choose where to go instead of letting the dogs go where they want, it raises your Seduction level. But if you want to raise Seduction rank very quickly, the fastest way to do so is via the Pub.
Just like the Brothel, you can approach Pub patrons and seduce them, eventually asking for money for your sexual services. Note that if you successfully do this enough times though Briar will notice what you're doing and you get whisked away to the Brothel for 'whoring without giving them their cut' as Briar 'owns all the whores in town'. But this doesn't happen if you fail to seduce the pub patrons or if you don't ask for money, and you still level Seduction if you fail, so the idea is to try as hard as you can to fail your seduction attempts. So this means showing up looking as conservative as possible (don't wear anything that has more than 1 dot in the clothing's 'reveal' stat), no makeup, etc.. Best done while Beauty stat is low, aka early in the game (Beauty increases passively over time). Because you look like someone from the Temple trying to seduce people, this will cause you to fail many seduction attempts in the Pub - raising your Seduction level while not losing anything in return for most part. The only time you might end up in a non-consensual encounter from this is if you ask for money and fail the seduction check (has a chance of happening when you fail while asking for money), so if your Seduction gets to the point where you have to also ask for money, you have to balance this risk of a non-consensual encounter with the risk of actually succeeding and instead upsetting Briar.
Fuck you, Jordan! You'll get yours, one day... 
