Select and trim for best glide, select field and plan how to get to it come first. Then try to identify reason for failure - reason for this is that all the time spent not finding the field is lessening your options.
The reason people tend to stick to their original choice even when a better field presents itself is mental overload - they don't have the capacity to change their plan. The solution is more practice.
Go around height - the better the approach is, the lower I let them get because this gives them confidence that it really would have worked and Im confident that if the engine fails to pick up when asked then we can land safely - I climb away much earlier when its clear they are making a mess of things and my options if the engine really fails are disappearing.
I did once have an engine cough and splutter when at about 100' - that concentrates the mind a bit!