There are many seemingly basic points which are overlooked in our practice. Particularly hope and fear, or rather not being concerned with them, during whichever sitting practice. In my limited experience, and from talking to others, it seems hope and fear come up a lot in relation to Yidam/Deity meditation. Then once the hope and/or fear are there, it becomes harder to do the actual practice and we potentially enter a destructive cycle and become uptight.

It doesn't have to be like this. If we relax, the whole thing will be more beneficial. When we are having problems visualising, we can simply relax for a bit before going back to the actual practice.

Worrying about the visualisation being unclear or somehow not complete is also pointless as Jamgon Kongtrul points out "the murky/unclear visualisation is also mind".