practice makes perfect, use to take me an hour to do the full repair of touchscreen replacement or anything. I learned that other technicians in the area do it in 20 minutes. This was starting to become a turning point for customers. Each repair now takes me a total 18minutes for the iPhone full repair. I use to follow the tape ways, etc but that was really slowing down the process.
My solution to you, when you take a screw out place it in front of you where u took it out, and make an invisible phone. So when u put them back you just put them back where they came from based on the invisible phone. Its also mostly you have to memorize each screw, its not as hard as you think. iPhone is one of the quickest and easiest repairs out there.