These are two big topics and a lot has been said about these on the internet. So, I will focus on few key points. In order to gain traction, you have to do some marketing. However, marketing has to be targeted towards early adopters and influencers. To attract them, your app has to be unique, engaging and solve one problem very well. Focus on getting your first 100 users from this group. Other things you can do is to reach out to various newsletters and blogs, fine tune the app store optimization for your app, make your app easy to share.
As for generating revenue, there are several models as well like ad-supported free app, freemium, in-app purchase, add-ons or cross sell. You have to think through which one makes most sense for your app. And none of these models work, if you don't have enough active/paying users. So, in early days, you have to focus on growth and expect to not make money for some time.