What mistakes to look out for technical seo

In terms of technical SEO there are a lot of mistakes that people early on their advancement in their site building process can encounter.
These include things that need to be careful of such as not having Duplicate content that can cannibalize your own well performing pages content, poor attention to mobile design.
Remember mobile design is as much if not more important than building a site for desktop as most searches now happen on mobile. Try to avoid low DA by not sharing your site links on low reputation sites that can be considered shady. Let's share some more mistakes you've found that can be avoided in the long run for technical SEO.

The part about not sharing your link on irrelevant or load domain Authority websites really resonated with me as I have a few examples of friends who had their website link to such shady or low credibility websites resulting in their sites on domain Authority being questioned and lowering their ranking