Actually some of those are true
Myth 1: You should submit your URLs to search engines. --
Either you do or not it's acceptable
Myth 2: You need a Google Sitemap. --
YES! it helps a lot in getting inner pages get indexed by Google bot
Myth 3: You need to update your site frequently --
It depends on the niche
Myth 4: PPC ads will help/hurt rankings. --
I don't agree on this
Myth 5: Your site will be banned if you ignore Google’s guidelines. --
Well that is if you cross the line and do black hat techniques
Myth 6: Your site will be banned if you buy links. --
If you get caught buying links your it's your rankings that will suffer.
Myth 7: H1 (or any header tags) must be used for high rankings. --
It can help if done properly
Myth 8: Words in your meta keyword tag have to be used on the page. --
YES! that's called on-page/content optimization 
Myth 9: SEO copy must be 250 words in length. --
I usually do more than 250, it's more effective if keywords are used
Myth 10: You need to optimize for the long tail. --
YES! why not? It's still part of your targeted keywords