Next up, screen shots. These can be a real pain in the ass, especially with a camera that does not let you manually focus.
What you need are a couple of rubber tipped quick-release clamps, like those used for gluing things. You can get them at most any large hardware shop. Use one of the clamps to grip the phone firmly as both the phone and clamp rest on the table's surface. Be careful not to crush the phone. You break it, you buy it.
Then use the second clamp to fasten the first clamp to the table. Now the phone is in a reasonably fixed position. You should be able to navigate the menus carefully without it moving a all. This is key.
Remember not to crush the phone when applying the clamps