Honestly the key is to be patient. Put it a low-ball offer on a .com you want then wait. They'll reject initially, then they'll contact you again every couple months to see if you're still interested. Keep the low-ball offers going, maybe increasing by very small increments. Eventually you will catch them in a moment where the seller is desperate and then you strike a deal. I got a 6 letters .com domain for $3k down…
Or maybe decreasing by very small amounts to show them the direction the negotiations are going to go if they keep it up.