Age- I don't really put as much weight on this but obviously the older the better. More importantly is who had owned the domain during it's life time. What do the use it for? Did they use it and abuse it then drop it?
PR- I look for anything over pr 4 but since I don't know your goals or what you are using it for or price range, then this might be a little rich for you.
DA- 30ish+
TF- 20ish+ This is an important one. I usually check this first if it doesn't pass this test then I pass on it immediately. Your standards may be lower or higher depending on your goals.
CF- Not as worried about this as long as everything else is in line.
Domain name- Is it brandable for what you are using it for?
-ahrefs- Important to check where the bl are coming from, nothing spammy looking.
-ahrefs- Look at anchor text, nothing spammy looking. High percentage of keywords? If so it might be a pass.
Another thing to look for is in ahrefs, click on the top pages and it will show the top pages of that domain, usually the top page is the home page but I uncovered some gold on one domain that I was able to pick up. The home page had PA57 TF26 but an internal page had PA63 TF42, it also had some other great internal pages.
Let me know if you have any questions about any of this.
Good Luck
-JC