I once met a fellow brewer who had built his own RIMS system. He had two temperature probes in his mash vessel and had fiddled with the engineering of the heating loop and wort return. He had also tweaked his process, varying how the wort was heated, his pump speed, etc., and finally arrived at a point that he was proud of. He could hold his mash temperatures steady, within only 0.5 °F (~0.25 °C) over time or between different places in the mash (except for inside the heating loop, obviously). He could program virtually any step mash into his controller and the rig would carry it out. He was very proud of his accomplishment (as he should have been) and he offered me one of his beers. It was contaminated.
In any process, the quality of the resulting product depends on the weakest link in the production chain. To use the above anecdote as an example, having a rock steady mash temperatures does not guard against contamination. If you understand this simple idea, you will instantly know how to improve your beers — fix the weakest link in your own chain.
What exactly your weakest link is depends on your setup and procedures. Maybe you don’t make yeast starters (or otherwise ensure that you are pitching the proper amount of yeast). Maybe you can’t control your fermentation temperatures. Maybe you use an inadequate method of aeration. Maybe you aren’t evaluating and using the freshest possible ingredients. Maybe you’ve stopped learning about brewing because you just want to follow recipes. It could be anything, but one thing is overwhelmingly likely — it’s not the aspect of brewing that you spend the most time on now. After I tried the contaminated beer I described above, the first question the guy asked me was if he should add another step to his step mash.
Unfortunately, I know that most of you will ignore this advice. When I told the guy above that his mash was fine, he needed to spend more time cleaning and sanitizing his fermentation equipment, he just said, “nah.” He knew that, at that point, I had been a brewer for years. He knew that I’ve studied brewing and wrote about it professionally for years. He knew that I had judged at many, many homebrew contests. However, he simply dismissed my criticism because it wasn’t what he wanted to hear.