I had read in some eBook that meta tags that do not matter too much now...anyways be sure and check it now
Well, using 30 keywords is spammy. Use keywords relevant to your site. Use around 10 keywords. They are fine. Concentrate more on META description.
Its OK if you won't put a meta keywords on your website. Focus on your description and your title tag. If you really want to put meta keywords, I would recommend to put atleast 6.
Meta tags contains important data related to site therefore it must contain all keywords of project which can target your site.
Google shows 69 Characters (Including Spaces) for Page Title. Google shows 156 Characters (Including Spaces) for Meta Description.
You should use 3-5 keyword in your meta tag, however if you have a keyword in your meta tag, you should also have a section on the page with your keyword in an H tag
Thats is correct,. Matt Cutts from Google has said that Google do not use meta tags anymore. However they use meta description.