When you're shooting film, you don't have the benefit of being able to check that you got the correct exposure after you take a shot like you do with digital. This great video will give you a couple common methods to ensure you get the exposure just right when you're shooting film.
Coming to you from Jay P. Morgan of The Slanted Lens, this helpful video will show you a few common ways to find the correct exposure for film, from using a dedicated light meter to the Sunny 16 rule. Personally, I just use a phone app to get me in the ballpark if I can't eyeball the exposure. It's not the same as an incident light meter, but it generally gets me close enough. Whatever you do, though, it is quite important to get your exposure correct, as unlike digital, you're paying for every frame you take. As Morgan notes, negative film tolerates overexposure remarkably better than digital does, so err on that side of things if you're in doubt. Once you've shot with film for a while, you'll get pretty used to eyeballing the exposure (which will help your digital work too). Check out the video above for the full rundown.