Like with any other industry, people are always looking for foolproof guides/strategies/whatever but the truth is, there’s no such thing. Domaining isn’t an exact science, there can never be guarantees.

For example:

Let’s assume someone makes you an offer for Domain1.com.

The truth is, there’s no such thing as a foolproof strategy about which you can say, without a shadow of a doubt, that it will surely 100% generate the highest possible revenue in that particular scenario.

Should you accept the best offer you get from that buyer for Domain1.com in order to reinvest in Domain2.com and Domain3.com?

Should you hang on to Domain1.com and wait for a better offer?

This is a common dilemma in the domaining world and again, nobody can guarantee that in any given case, one strategy or another is without a doubt the best solution.

Maybe if you hang on to Domain1.com, a new buyer will make a considerably higher offer one week from now.

On the other hand, maybe nobody will ever make an offer as high as the one you said no to.

You don’t know… you can’t know, all you can do is use your knowledge + gut feeling to make an educated guess.