What will be your next steps if your SEO methods or technique does not work?

Hello Friends,
My first attempt would to try analysis the problem and resolve them step by step

Firstly I would try to see whether it is a new project, and then like to re-check the keywords.
Also, I would look for relevant keywords that can be helpful.
Even though the webpage and website have been indexed well and still not appearing on the first 10 pages of search engine result page, then I would make some changes in page text, titles, and description.
If the website is not indexed well or dropped from the index, then it might comprise serious issues, and re-work might be required.

Write Long Blog Posts.
Use the Bucket Brigade Copywriting Technique.
Keep Updating Old Content.
Get Quality Backlinks.
Research Your Keywords Well.
Write RankBrain-Friendly Content.