There is no said way that will give you a guaranteed solid income for an extended period of time. It all comes down to how much you want to work and what area you want to work in. Signature campaigns are a great way to start earning money and is relatively stable, provided you write the minimum amount of posts and not break any campaign rules. Another great, stable way to earn bitcoin is to sell your services. I guess it comes down to how much time you want to invest in it to make it a stable income. If you are lazy and don't commit, then you might not get paid and then it won't be a stable source of income. If you do, then you can make a decent amount in a relatively short amount of time.