The easiest way to get a bitcoin is to buy it. Other than than that, there is no easy way to have a bitcoin. You apply signature campaign but it will take a long time to make your earnings to be a whole bitcoin. You have a lot of work to do before you can have a bitcoin.
Getting your first bitcoin can be done with all kind of methods of course, one of the best methods is doing a signature campaign because its easy and also pretty safe, keep in mind its different at every signature campaign plus your forum rank.