It's of course always better if you know the CEOs in person or can get in touch via intro.
If you don't know them but there is some connection to them or to their company and if it's just that you like their product or brand, just write them. People say that cold mails are bad. I think they are only bad if you could have reached the person via intro. Otherwise they are better than doing nothing. And at the end, it's just a number game.
Re the emails and how they should look like: there is really no right and wrong. The best advice I can give: Just imagine if you were writing a good friend. Then your email will be balanced: not too needy or too formal. Keep it short, tell him who you are, why you write him and suggest a next step.
If you don't know them but there is some connection to them or to their company and if it's just that you like their product or brand, just write them. People say that cold mails are bad. I think they are only bad if you could have reached the person via intro. Otherwise they are better than doing nothing. And at the end, it's just a number game.
Re the emails and how they should look like: there is really no right and wrong. The best advice I can give: Just imagine if you were writing a good friend. Then your email will be balanced: not too needy or too formal. Keep it short, tell him who you are, why you write him and suggest a next step.