GADGET
Determine what you are comfortable spending. These are also available in different price ranges, so establishing a budget eliminates some of the options for you.
Reflect on how you use phone. Do you have gaming or photography, in mind or do you just need it for daily work? This should help you to decide what features are more important.
You're going to use your screen as a keyboard and mouse, and it's going to be your main interface. Resolution, panel type and refresh rate for the right viewing experience.
Battery life is important, especially for those heavy users. Take a look at the battery life and how fast it can be charged so that your phone does not die on you halfway.
Check that the phone you have uses enough storage for your requirements and see if an expendable option is available.