They are usually the only ones that understand the patience/risk involved. Most new players try a couple times, die and get looted, and are like..fuck that.
You're basically dying to the same few players every time you get assassinated and they just happen to be really good/patient/understanding of the skill to make it work.
Pretty much just:
1. Understand this is going to take between 100-200 hours IC.
2. Understand you need to gear for hp like a mage.
3. Understand you need to level sit until you have a high %.
4. Understand you always exploit a vuln when possible.
5. Understand people are going to hate you and full sac you if you die.
6. Understand you will have 20-30 misses between each success until about 80% depending on RNG and blind luck.
7. Understand the skill isn't for casual players, you will be spending hours a day just hoping someone logs in that you can actually stalk.