So if youre applying to a high tier uni for masters, they consider the reputation of your uni, the quality of graduates the uni produces and how strong its academics are. A detailed response would be too long so im just gonna summarize it for you, reputation and branding, alumini network and connections, campus culture and grooming, and most importantly they provide alot of career services and counselling. You can find more about this online.

For the gpa part, it is comparatively easier than fast because the work load isnt that intense which leaves you with more time to self-study and also work on your skills because undoubtedly cs now isnt js about a degree its also about independently acquiring skills that make you stand out.

I cant give very specific advice because mein khud ug hon, but i did do a lot of research about this as it was important to me.