MacBook Pro retina 13" with wobbly screen how to you fix?

"In most cases you can open the bottom cover to access the hinge screws which maybe loose here. But without more clarity and a exact model to work from we really can give you more.

Update

Here is the IFIXIT guide on how to disassemble your system to gain access to the display assembly: MacBook Pro 13"" Retina Display Late 2012 Display Assembly Replacement.

After you power down your system follow the steps down Step 9 so your battery is disconnected. As we are not pulling the display fully out, you can jump over the next few steps. Jumping to Step 15 here is where we are gaining access to the hinges and the screws.

Make sure you don't move the display going forward here as you can damage the cables if you are not careful!

All you want to do is check the screws to make sure they are tight. You can use some clear fingernail polish to help lock down the screws. just don't go overboard here! A little goes a long way. Loosen the screw a bit and give a small wipe just under the head of the screw and retighten.

If you find the lid is still loose the hinge unit within the display assembly is likely loose. At that point follow Nate's link below on gaining access to the lid screws."