How to Increase Website Traffic For WordPress and Blogger

I work part time for a local company every Wednesday and Friday, my job is to increase organic traffic to their website. When I first join the website has no traffic at all and only contain 8 articles including posts and pages. The website age is one year.
Optimization steps I did for the website:

On page:

1. Change the website themes as per their request, I add a custom slider contain 3 images.
2. Looking for a competition website and their traffic value using Ahrefs
3. Check their keyword by looking at their URL or title and them with Keywords Everywhere, at this point I didn’t care about the competition. I just looking for keywords with good search volume.
4. Order articles based on the keywords, if I found the first position has 2000 articles, then we order more than 2000 words.
5. Add relevant pictures on the article and give proper alt text and description

Off page:

I looking for a personal blog that good in metrics according to Ahrefs and also have enough visitor
Contact the owner to see the chance to make a guest posting. I will make sure the link went to related article on our website.
I repeat this to 15 blogs.

I create posts on forum

Create posting on web 2.0 website

All backlink point to posts that related to our website.

I started the work in July 2019 and below is the result according to Histats.
Total published post for this website is 204 but only 37 articles that well researched, the rest is product post that I consider thin content.

I have an abandoned website that already 5years old, the domain is empty but I use subdomain and installed WordPress. Later I decided to move to blogger using the same domain name.

Onpage:
Order or create article minimum 500 words
Add relevant photos/pictures
Fill all alt dan description on each pictures.

Offpage:
guest post on relevant website
forum post

Theme/template changes (WordPress and Blogger)

If you already have stable traffic be careful with changing the theme, there is potential traffic decrease or increase as the search engine will see the different structure of the new theme.

To minimize traffic decrease you have to make sure that the search engine will see no changes on your meta title tag, meta description, and meta keywords.

To check your meta tags use https://smallseotools.com/meta-tags-analyzer/ make sure the values are same between before and after theme changes.

Write down or take a screenshot of meta title value, meta keyword value (if exist), and meta description value (if exist). Make sure when you have moved to the new theme, those values remain the same with your old theme.

This is how we can mitigate the drop traffic effect after changing the website’s theme. For the theme structure, we cannot do much about this. Just make sure your new theme is better from the old one by gathering information or reading testimonials from people who have used it before.