Blender rendering quality pixelated I've slowly been getting better at blender but one thing that annoys me a lot is that when i press F12 to render my scene, well, it's all pixelated. 
Examles: 

So this here is something i was testing out, and this is when i press Shift+Z



So that's fine and all but then i go to F12 and i get this:


Now, i have read other peoples posts, and they call say "duplicate" and they all have answers, now honestly it annoys me that none of them have a good answer that actually would aid this. I've read all the things i could find, and some of the "Similar questions" and some people have the same problem as me, but i doubt there is nothing i can do?

TL;DR Want to make my renders not pixelated so i can make the low-poly scenes i've been making better. So i can actually zoom in without seeing pixels.
looks like a low res zoomed image. check your render resolution, X, Y and %. a 1000x1000 render at 25% gives a 250x250 image. Aspect ratio has to be 1.