How can I know the strength to choose a name that can rank well?
all TLDs can rank well... ok, maybe .xyz might be considered spam by google so they might give this TLD a harder time to rank (although I'm still not 100% sure), but otherwise any TLD that you pick can rank
Regarding what makes domain names good I would say these...
- it's short (not more than 8-10 characters long, but obviously the shorter the better. A domain like x.com, for example, will be accessed even by people who - through some miracle - have no idea what X is, even if only out of sheer curiosity or accidental typing)
- it's catchy, brandable, interesting, or any combination of these 3
- it's devoid of numbers, special characters, or hyphens (of course, there are domain names out there that are doing well despite of containing numbers or hyphens... and, sometimes, containing numbers is pretty crucial even, take for example the domain names of popular games like Path of Exile who just launched their new game Path of Exile 2 so they had to choose the domain pathofexile2.com for their new game, in such cases having numbers in the domain is actually recommended in order to direct people to the right game... but otherwise, aside from these special cases, you should generally avoid owning domains with numbers or hyphens in them, makes the typing and remembering of the domain much easier for your potential viewers)
- it's not blacklisted / flagged / penalized by google (this one's hard to tell and requires some more research, personally I have no idea how to tell whether a domain had been blacklisted or flagged by google, but if you buy one that's been screwed up by this mafia company just because it doesn't fit into their imbecile monopolistic rules you almost guaranteed will not be able to rank that domain no matter what you do)
And I think these are pretty much the 4 most important rules of good domain names...
