Meta keywords should not be ignored, though they are not a major ranking factor for most of search engines nowadays. A Meta keywords tag is supposed to be a brief and concise list of the most important themes of your page

Tips:
1. keep your list of keywords or keyword phrases down to 10 - 20 unique words or phrases.
2. separate the words or phrases using a comma (you do not need to leave a space between words separated by commas).
3. do not repeat words or phrases.
4. put your most important word or phrases at the beginning of your list.

Robots.txt file can be used to regulate access of search engine crawlers, properly configured robots.txt file can help
crawlers to better understand your website.

Tips:
1. grand robots access to those pages you wish them to crawl.
2. restrict access to those pages you do not wish search engines to see and crawl.

Sitemap helps search engine crawler to identify your website pages.

Tips:
1. ensure all your important pages are listed in the sitemap.
2. ensure to indicate the frequency of change and importance of each url.
3. inform search engines of the location/URL of your sitemap (eg, For Google, you can set the website sitemap location through Google Webmaster management panel).

Search Engines treat URLs with or without "www" as two different records.

Tips:
1. edit your .htaccess file and permanently redirect one to the other (eg redirect www.mysite.com to mysite.com).

reasonable number of links (below 100) per page will give a better user experience.


Tips:
1. keep the number of links per page below 100.
2. having more than 100 links in a single page will lead to a bad user experience, and it possibly runs into the risk of been considered as spam.
3. search engines may not follow all the links if you have too many of them in a single page.

put scripts together and link them from an external files rather then put them in the same file as the main page.

Tips:
1. reduce the use of in-page scripts, put them in separate files and link them in.
2. reduce the number of external script files, it will help browser to make lesser number of http requests from the server.
3. optimize or compress the script files to have smaller size and faster loading.

Users are concerned about the safety of their online transactions. Trustworthiness rating is based on real user ratings and that tells you how much other users trust this site, so do the serch engines. note: this trustworthiness score is provided by WOT (Web of Trust).

Tips:
1. pay attention to the look and design of your site, many people look for visual cues when assessing a site`s credibility
2. make your site easy to use, sites that are easy to navigate are perceived as being more trustworthy.
3. make it easy for user to contact you, users will be more comfortable and feel more secured shall they need to get in touch with you.

Too many domains hosted on the same server is an indicator that you are not really serious about your website, and your site will have a higher chance to be surrounded by bad neighbours.

Tips:
1. the fewer domains hosted on the same server/ip the better.
2. avoid shared hosting whenever possible, especially when there are already hundreds or thousands of sites are hosted on the same server.
3. dedicated ip or resources for your site not only do good to your site visitors but also favoured by search engines.