Firstly, you need to decide on a size. Most laptops will be 13- or 15in but you can also go smaller or larger if you want something even more portable or if it rarely needs to move. Remember that the size of the screen will have an impact on things like the weight of the laptop and other things like the keyboard and even how many ports and connections it can have. It's typical to find a budget laptop with an unexciting resolution of 1366x768 (HD) but if you can find higher, probably 1920x1080 (or Full HD) then you'll be much better off. Look for a matt finish which is preferable to a glossy screen that reflects like a mirror when it's bright and sunny. You'll also want to look out for the type of display and this is often an area where costs are cut so viewing angles can be poor as well as brightness and colour. Get an IPS rather than TN screen if you can.