You can visit their public profile blog page in steemit and read their short description about the ID which is written just below the display name.
Here are the example and screenshot of a bot and human account and this is one way to identify a bot account or a human account in steemit.
Example of a Bot Account
Example of a Human Account
You can clearly see the description of the account in their public profile page and in the first screenshot it says to send the bid to get an upvote that means that is a bot account and in the later there is no such description of commercial purpose in steem community.
The other thing you can notice that whenever a bot puts a comment it is a ready-made and universal comment like "you have received an upvote of 2.4% from@bot"...."thank you for choosing the service of @bot" etc.
Thank you and Have a great day.
Bots accounts usually uses pre-set sentences in their replies. For example "Wow what a nice photo, I upvotes your post, please upvote my posts too"
Unless explicitly stated, that an account is controlled by a bot, it's near impossible.
Many users run a on their Personal account when they are not active for various purposes.