Hey Catalin! I'm thrilled to hear you liked the blogging course :) Let me try and answer your questions.
1. How do you monetize your blog?
For me personally, my most monetized blog is about travel (itineraries, travel guides, things to do, etc) and it's monetized in two ways: affiliate marketing and advertising.
With affiliate marketing, you earn money by referring people to products or services. On my website, this is usually Airbnbs, hotels, tours, and travel and photography gear.
With ads, you can join different kind of ad networks depending on how much traffic your website receives and from where (geographically). The important thing to understand is that there are MANY more options besides Adsense. For instance, I'm a member of Mediavine.
I don't personally sell digital products but this is also a popular option.
2. At what point can you start monetizing your blog?
With affiliate marketing or selling your own digital products, you can do it right away. The important thing is to write articles that people are likely to search for when they are already looking to make a purchase (also called "commercial intent").
That said, there is a big difference between starting a website with the "mindset" of making money from it vs. having an existing website and trying to make money from it.
The latter is often much more difficult. I recommend that people start thinking about their monetization strategy before buying the domain, if possible.
3. How do you improve your position in search engine results?
This is a very big question! But the short answer is:
Look at Page 1 of Google for the keyword you want to rank for, figure out why those pages are ranking instead of you, and then do that for your website.
You may find those sites match the search intent better, cover more topics, have more backlinks, are on more authoritative websites, receive pagerank from internal links from other articles, etc.
Ultimately it's all about reverse-engineering why the top results are ranking and applying that to your website!
Happy to clarify if you have any follow up questions :)