It actually depends on two factors, how popular your website is online, its rankings on search engines and the traffic is receives on a daily basis and also the commissions paid by the affiliate program you have recently joined. usually, the first point is far more significant because when you own a highly visited website, you will be able to find dozens of top-paying affiliate networks online.
One of the reasons why many people are not able to earn a monthly income from affiliate programs is because their sites are not accessed by many visitors everyday and so, there will not be a lot of clicks on the ads and text links. The priority is to promote your website, work on its SEO aspects and then look for the lucrative projects and there are so many of them.