No, I don't mean keep focus as in "Staying focused" as in "Focus in what you are doing"
I mean focus as in, "the image is blurry" or "Can't see a clear picture"
When you are working on a Project, no matter if you are working alone or with teammates, you are assigned (or assign yourself) to one specific task at a time, and even if you multi task some different things at once, you just can't make THE WHOLE project at once.
You gotta start somewhere, and then go somewhere else, and then somewhere else, and those parts that you complete, well you won't really be seeing them again for a while, since you'll be working on the other parts.
Yeah testing the whole project can fix that, but once you "lockdown" a part, you just won't touch it again, and you gotta focus on the parts that are still not complete.
My point is, when you spend 2 weeks working on a tunnel, your view starts narrowing down to that tunnel and sometimes, you might encounter yourself feeling "this is it? Two weeks for a bloody tunnel."
It's important to sometimes, step back from that tunnel, and look back at the project in it's entirety, because looking just at that tunnel that just won't look as good as you imagine it, well it can demotivate you pretty badly...
So sometimes step back, and see the whole picture, look at your whole project, and try to piece the ENTIRE thing in your head, to see where you are going.
This helps getting out of that tunnel...
The problem is getting back in, but once you are motivated it gets easier.