Once I get a backlink from a desired site will it be beneficial to get more links from the same site or should I move on and find other sites. Thanks.
If you have already sourced a link from a website, IMHO, it would not make sense to source more links from the same website. Google considers links coming from unique IPs in tandem with other quality parameters. It would therefore not give you much or any value for the link.
well it is always good to have links from various sources but if you are interested in getting more links from the same source then also is will definitely help you. however there is one condition for that those links coming form same source should be from good pages having high pr.