Yes, it's hard, and I'm not sure there are general strategies that always work.
It's fundamentally the same problem that the company is trying to solve when they interview you, just the other way 'round.
Some ideas: observe and ask in the interviews and hiring process in general. See what you can find out about the company from friends, contacts and even strangers. Network! Do some online research, too.
Something I've found useful is just reaching out to past employees. Usually folks that don't work there anymore will be more transparent. Only challenge is getting someone to respond to you, but you'd be surprised how many folks will talk if you don't come off like you're trying to sell them something or a bot.
It's fundamentally the same problem that the company is trying to solve when they interview you, just the other way 'round.
Some ideas: observe and ask in the interviews and hiring process in general. See what you can find out about the company from friends, contacts and even strangers. Network! Do some online research, too.
Btw, lots of the cliché interview questions ("What are your greatest weaknesses?" etc) actually make decent questions you can ask about the company and team you are about to join.