If I do only off page for my site, and I will not do any type of onpage. Just randomly will choose a tittle for my site and will do all off pages. Does this any harm for my website ?
But for keywords you have to analyse your site with proper keywords & competition. Then with title & meta tags you can start off-page optimization
No it will not do any harm, but why will you not do onpage if necessity avails? Your meta tags and content is satisfactory?
Say you build backlinks for "website design cityx" and the content of your website is "farming countyy" - the content and the backlinks don't support each other and I would expect this website to do worse than one that has onpagew and offpage both relating. Afterall, Google doesn't want to be sending website design enquiries off to a farming website - it would alienate its search customers.
before starting off on page its must importer to to understand that winch title key words are mainly targeted for which pages
By having enough high quality KEYWORD anchor text links pointing to your page, you can get away with not having any onpage seo. you will not need as many high quality anchor text links if you have on page seo as well. The only reason for you not to do onpage seo, is if your website is 100% flash, in which case I would find a new web design company.
You should always follow Googles webmaster tools central Search Engine Optimization Guide. This explains exactly what will and will not harm your site. On page SEO is always beneficial. And flash text can now be picked up in googles search engines. You just need to use selectable text options within your movie. Cheers