It can be good to try in a store before you buy.
There's a trade-off between laptop screen size and weight/portability and battery life. If you don't need any portability a desktop and monitor should be cheaper. As others have suggested an external monitor is an option.
A higher screen resolution looks less grainy, and allows you to fit more text on the screen, but at a smaller size. What works for one person, doesn't for another.
A back-lit keyboard is handy, but perhaps a luxury. Do check the layout of the keys surrounding the edge of the keyboard, are they where you would expect them to be? Does the keyboard bend in the middle as you type?
Harder to check is performance. I would think for your purposes all recent laptops have sufficient CPU and RAM. You could consider investing in a solid state hard drive for a quicker start up. The trade-off is they tend to be smaller - 128 Gb is fine for the operating system and programs, but you will have to consider how much room your other files will take up (images, music, videos).
Glossy screens are vibrant, but more reflective in natural light. Touch screens are great to use (so I have been told), but as well as glossier screens, tend to have worse battery life.
I assume all laptops have reasonable wireless. I use a Bluetooth mouse. A few USB 3.0 ports are always handy. Need to connect to a TV/monitor, headphones, a SD Card reader or a built-in camera?