My first batch of beer was very complicated with lots of different ingredients and to be honest I wasn't even sure exactly what I was doing. In my second batch I decided to go "neutral," making a smaller batch (5 liters) and used only Pilsner, only Saaz and single infusion (to see the impact of each ingredient, and from there evolve). The beer is ready but now I'm kind of clueless to where to go. Is there any other way to see the impact of each ingredient without actually brewing a batch? I want to know how temperature, yeast, malt, etc. act on the beer.
This discussion would be more suitable in the homebrew stack as Andrew said, but I will answer it anyway.
You are on the right track, making a simple pilsner recipe will show you the effects of the malt, yeast, water and hops.
There is a technique called SMASH (single malt, single hops), which is widely used to "test" the effect of a new ingredient. It is pretty much exactly what you are doing.
The best technique: brew as often as possible. Be critical of your beer. Get a BJCP judge (or similar) to try your beer and give you feedback.
Relax, dont worry, have a homebrew. (Papasian).