First, Google is your friend! You can find out so much just by researching and reading everything you can online. What is the best advice? ALL OF IT! Seriously! There are many roads to becoming an actor and many different ways to find success. Read them all and then cultivate what works the best for YOU. There is no 'one way' nor any special magic. It is a road built on persistence, continual learning and putting yourself out there. You could hear a thousands no's before a yes or you could be booked on the first thing you audition for, the road is different for everyone.
Here are some things that can help make it a little easier.
First, those awesome new headshots we just took, now you have to do something with them. Or many things! Don't let them sit in your collection, waiting for a producer to call me looking for your type (though that has happened!!) Now it is your turn to start plastering your face everywhere you can!
Important sites to have a profile on. Yes, you have to pay for these sites. Yes, you have to pay to upload your headshots. That is just the nature of the beast. It is a lot cheaper than it used to be. When I was starting out as an actor 30 years ago, (yes, I was a kid), I (or my mom) had to pay a lot of money to print physical copies of my headshot to send all over town. I had to leave one or two at every audition that I went to. We spent a fortune in printing and shipping costs. Now it is a lot easier and these sites have made it very easy to get your face seen!
Once you have your profile on the sites, don't just let it sit there. You need to actively be checking the sites (daily) and self submitting yourself for any roles that you think you might be right for. Keep all your contact information up to date and submit! submit! submit!! I know people who check hourly for new postings. They can go up at anytime. Day or Night.
It is good to always keep about 20 physical copies of your headshots on hand. Every once in a blue moon, I've had a request for one, so it is better to be the person who can whip it out from your back pocket.