u/Significant-Bag-7471

So, I am having a hard time dealing with slack tricks because I don't know how to control it properly like everytime I do one it just doesn't look good and I can't find the reason why it doesn't look good, so here I am asking for tips on how to control them properly and some tricks for the fundamentals of slacks, the only thing I know is about string tension but other than that it's close to none, so any help will do! Thank you in advance