How to get head-hunted for leading roles

The best way to do this is to build up your cv from scratch. Go through it with a fine comb, anything that people will not recognise remove, keep decent, great credits on your cv and update your showreel. Use clips that really show you off to your full ability. Have a wide range of scenes from different films.

A showreel is so important for casting directors who don't know of your work.

It's easier if you have a particular genre you want to work in, ie romance,comedy,horror etc

With the horror world the more horror you do the more people will recognise you and will get more people from the industry contacting you. The more comedy you do, the more people in the comedy world will start to pay attention to you.

Start small, yet make sure you connect with the role and that it is something you enjoy reading and that you would really like to do.

There are so many bad scripts around, bad productions, so, do many projects yet be careful it's a script and role people will see you in and respect you for doing.
The more work you do the more people will know you and call you in.

The more work people see you in the more your name will be recognised.

Even if you are working, don't stop contacting casting directors/directors/producers. Let these people know what you are working on and where they can see your work.

Do great roles, great scripts with great people. Trust me, people will notice you and call you in for bigger and better roles.
Don't be afraid to say no to roles, even if they are paying well, some roles just are not worth your time.
Understand your talent and what you are worth.

Have an open mind and read the script thoroughly.