Well being a detective won't be easy, those requires hard work. But it usually questions will you able to see corpse and that's one major test you have to pass through if you seriously want to be one. Being smart is one thing, but it always boils down to one major point, are you good at piecing pieces together to understand who is the culprit with gathered references. We learn a lot from reading detective conan because we already know there are many ways and types of understanding case even difficult ones.
One way to hone detective skills is always improvise. If you're not good at Maths, science, English, it does not make you bad detective! If you're observant enough and keen to do well I don't see why not to be detective, it takes hard work. Majorly cases ask you to think out of box so it usually ask your lateral thinking not only on evidence it always boil down to draw conclusion of the case.
I didn't study but did practical exercise with group in past at high school, but nowadays I didn't pull my brain together thinking 'cause I'm being git for not thinking through cases I read, it's too many before I could jump conclusions Conan work and save the day. XD I become 'bystander' of the case and really try to put head together here but it didn't come out well when I 'type' theory.
Recently I change monitor and suddenly had clear head I'm thankful I start to put on thinking cap on. In high school I remember teacher did provide insight of being detective, if you're lucky to have one testing you out with practical 'handnotes' you may able to work as detective if doing different exercise endlessly everyday. Conan is smart, even he's tone deaf he still can work it out, he learn long how to reach out and get things he want and he's highly intelligent we see on anime, and tv.
Research is one thing, science help to draw out conclusions, but become hard-core detective like Heiji and Conan it basically it's not about knowledge any more because one has to be careful of bait culprit may put to lure detectives think other way. This sort call 'hard core' detective might exist in Japan because of security can afford for high performance in country.
Hajimi Kindaichi may not be focus in study but he's smart enough to draw conclusions of case without using extensive knowledge, being detective one has to aware of pitfalls and observe fishiness of situation and location providing on spot. Cops can crack case because they won't take in evidence enough as good excuse and really put their minds together focusing on criminal minds and small evidence of evidence tamper.