How I have doubled the convertion rate of my landing page

First, short background info: I've made a browser extension (Altruisto.com) so that when users shop online, a portion of the money they pay goes to highly effective, evidence-backed charities. Works with over 1000+ stores, including eBay, Aliexpress, Etsy etc. (that's important for later).

When I've launched it, I haven't put too much thought into the landing page, I just wanted to have something ready and ship it as fast as I could. It was just a typical landing I pulled together in a few short hours. Its conversion rate was at ~12-14% (unique visitors to extension installs).

Because I received some funds for marketing, I've decided to improve the conversion rate first, so that the money wouldn't get wasted.

Here are the things I've done to improve the conversion 2x (and on a traffic from one specific source even 3x). Many of them were based on suggestions from Flint McGlaughlin -- he made a video analyzing how we could improve the LP (you can find the link to the video at the end of this post).

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• Added "find out more" link to the first screen.
  In the previous version, the only CTA was installing the extension. It's a lot to ask from a first time visitor who doesn't know much about the initiative, etc. so it makes sense to add an option to read more before making the decision. Obviously, the visitor could just scroll down the page, but adding a link makes it clear that you don't have to make your decision right away.

• Changed the first section after the fold to be more interesting.
  Previously it was "No costs for you" that was assuring that you don't pay a penny extra because of using the extension. I thought this would be the most common objection so I wanted to address it as quickly as possible. The problem is... the person doesn't even know if she wants to install the extension at all. So it's not the place to talk about objections. Objections arise just before making the decision, not when you don't even know if you're interested at all.
  So the goal of the first section is to make person INTERESTED in what is offered. Therefore I've changed that section to make it more benefit-oriented. Now it says "See how much difference you can make" and shows that with a typical purchase, a person can, for example, provide cure from parasites for three children. Just by installing the extension.
  (I've moved the "no costs" info to the section explaining how everything works).

• Made it easier to understand at a glance.
  I am nerdy, I like reading, I like science so I've made a nerdy website with a lot of text explaining that supported charities are backed by randomized controlled trials and how much can be done with how little money. And that schistosomiasis (the word I can’t even pronounce) is super bad but super cheap to cure. And this and that. It all made it difficult to GRASP IN SECONDS what this thing is all about.
  Therefore I’ve rewritten headlines and added short explanations, and I’ve put details in pop-ups. If someone is skeptical and needs to see the calculations, references, etc. – they are available. But most people won’t spend time doing that.
  The website became way clearer and easier to understand.

• Added more CTA buttons throughout the page.
  In the previous version, there was the CTA button on the first screen and in the upper menu. I've added extra buttons throughout the page so at any point the visitor can easily take action (without having to scroll back to the top or look for the button in the menu).

• Added more big brands’ logos.
  In the previous version, there were only three logos – aliexpress, etsy, barnes&noble. Now I’ve added eBay, Microsoft, and Booking. First of all, Microsoft’s or eBay’s logos are more recognizable, I think. Especially outside of the US. Secondly, I have a hypothesis that three logos fall into „a few” category, whereas six logos fall more often into „a lot” category. And a thought „there are a lot of big brands working with this extension” is much better than „there are a few big brands working with this extension”.

• Added „Talking about us” section (social proof).
  Altruisto was shared on twitter by Peter Singer and Steven Pinker – quite recognizable figures, especially in my core target group. So I’ve embedded their tweets (plus two others).

• Put more emphasis on trustworthiness
  Altruisto has an open source code (I try to make everything as transparent as possible) and is registered as Social Enterprise. In the previous website, I’ve mentioned it at the bottom of the page, in the FAQ section. Now I’ve exposed those two pieces of information more as I’ve found out that even some of my close friends didn’t know about them…

• Added inline installation.
  Previously clicking „Install” button would take the user to Chrome Webstore where she would have to click another button „add to Chrome”. Now, I’ve used inline installation feature, which means that the user can install the extension without leaving the page.

• Addressed frequent objection in the inline installation screen.
  Quite a few people were concerned about the permissions that the extension requires, so I've added an explanation why these permissions are needed and how it protects users' privacy. And also that the source code is available for everyone to audit and make sure that it works as it should.

• Longer FAQ
  I've answered more questions/concerns that people had in the conversations I had about Altruisto.

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• I was also thinking about adding some security badges, but McAfee's costs (if I remember correctly) $40/month and I thought using some generic ones looks lame.

• I am just about to launch press outreach campaign so I will probably add „as seen in” section as well to get even more social proof.

Now, I am not sure which changes had the biggest impact and which were insignificant. But... I DON'T THINK A/B TESTING EACH OF THEM MAKES ANY SENSE AT ALL.

Here's why: I don't have much traffic, so it's improbable that I would get statistically significant differences, plus testing each of them separately would take weeks if not months. Therefore I figured it's better to implement at once all the changes that, based on the knowledge I have (and some common sense), should move the needle.

You can see the current LP at https://altruisto.com
And you can see the previous one (with an analysis of mistakes I've made) in this video: https://www.youtube.com/watch?v=D-3AAozKkLU