Well in some of my lucids, I have trouble summoning things, especially people.

While I was bored at school, I thought about lucid dreaming, and had the idea of remembering where the thing/person was other than expecting them to be there.

So for example.

You're lost in a forest looking for a magical key that will help you unlock the magic voodoo door.

Instead of saying "I expect the key to be in my pocket"
How well would it work if you said, "Hey! I remember where the key was! It was in my pocket the whole time!"
And then reach in and grab it.