This question is not clear at all. Let me explore how many assumptions it has.
I saw the same clip edited
You are assuming that the other person is using the same clip. He probably had a better resolution one. But here I am assuming the other clip looked better than yours.
He could have just imported a similar resolution clip, let's say extracted from a DVD, and probably it was simply resampled on a FullHD project.
So, no way to respond to that part.
But I will answer this:
1080p so I want to know what setting I must use to render that kind of video
Prepare a project of the resolution you intent, in this case... 1080p
I tried rendering it on 1080p but the effects that I added did not work.
Here are again on the realm of "what are we talking about?" What effects?
Again. Simply prepare a project of the intended resolution you want to deliver from the start.
It has two advantages
The "effects" or elements will render at the real resolution. If you prepare a project smaller, this simply will produce a blurry or pixelated project.
You do not force your equipment making a project bigger. If you prepare a project bigger, your workflow could simply get slower, less fluid.
But if there is a chance you actually need a project bigger at a future time, yes you can prepare it that way and deliver the first version resampled down.