White Hat SEO should really be the base of your work, and you should always primarily rely on it as it will bring you results in a long-terms and it's the only safe and proven optimization method. On the other hand, if you need some quick results, you can turn on to some Black Hat methods, but that shouldn't be your regular practice as if you go too deep in it you will get used to doing only scammy things which will damage your online reputation or even get you banned from the ranking.