system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What makes a scientific study a good one? what are the best practices?

Like, control groups, placebo, whatever. I don't have much knowledge about it.
And how to check when some study seems reliable but it's actually flawed?

Thanks.
gpt
It's almost impossible to tell if a study is flawed, unless you are an expert in the topic.  Instead you could see if the results have been replicated by other people.  By the time you see 3-5 papers published that confirm a result, that's pretty good evidence that the study is true.  It's also **super important** to read the actual scientific study, even though it might be really hard to decode, because the "science news coverage" is likely to be wildly different than the actual paper that was published.