Cloak has more counters then any other skill in the game but it also very powerful if you get it off. I will speak from standpoint of my stamblade.

Assuming no counter skill/pot is being used against you should know that any and all damage taken at the moment you pop the cloak skill will cause it to fail. The best way to counter this issue is to dodge roll right before cloaking and hope no un-dodgeable attack is incoming.

Also AoE damage will pop you right back out even if you get the cloak off so you will need to get space between you any class spamming an AoE.

In short, the best way to maximize your chances of using cloak effectively is to combine it with speed and dodge roll. For me this means having bow on my cloak bar so when I dodge roll I get major expedition. I also unfortunately have to waste a slot on concealed weapon which I never use but the passive speed buff while cloaked (25%) is critical imo. I also have alliance skill Rapids on back bar for when things go bad and I need sustained speed+snare immunity+immov pot for extra distance before I try to cloak again.

However, there is also a steep learning curve to the proper timing and the judicious use of cloak given the limited magicka pool. This will come with time and experience. However, even doing all these things can still result in failure against good players using hard counters but your success ratio will improve dramatically.

Hehe, yall remember ganking before Morrowwind? I remember.