When you have a small screen it is hard to find the right resolution for the session.

My setup/requirements:

• the Window needs to fit on a 13“ screen
• no scroll bars
• optimized for low bandwidth and high latency
• send the Windows key to the remote computer (Win2012 start menu, Win+e, …)
• don’t redirect printers/smartcard readers
• don’t show the last server I connected to

There is a hidden file in %userprofile%\Documents\ called Default.rdp where you can predefine settings.
In my case I changed/added the following lines:

screen mode id:i:1
desktopwidth:i:1230
desktopheight:i:715
winposstr:s:0,1,0,0,2000,2000
smart sizing:i:1 
connection type:i:1
session bpp:i:16
keyboardhook:i:1
redirectprinters:i:0
redirectsmartcards:i:0
full address:s:

Protect the file by making it read-only. Otherwise it might get replaced when you close the RDP session.

Here is a full list of the available options:
technet.microsoft.com