What are the SEO Mistakes that should be avoided?

[grofee]

On-Page SEO Mistakes to be avoided:
1) Duplicate Content
2) Broken Images and Missing Alt Tags
3) Using No-follow Tags to Hide Pages
4) Poor Quality External Links
5) Poorly Structured Internal Links
6) Slow Page Loading Speed
7) Poorly Optimized Title Tags and Meta Descriptions
Neglecting LSI Keywords
9) Thin Content Pages
10) Concentrating on Only On-Page SEO