I tell myself to look objectively at the position: do I really hold an advantage, or is it just wishful thinking? If I am going for a win then where is it going to come from? What advantages do I hold that can lead to a winning superiority? If there are none then I need to create them. Do not try to force a win in a position that is balanced, unless I can find a combination.
Be honest: can I afford to attack or am I on the defensive?
Wishful thinking will more likely lead to a loss than a win.