Can any one suggest, what's a process to get/improve back link on Bing ?
IN order to get more back links in bing. bing prefer quality to quantity and that "Backlinks should be relevant to the page being linked to or relevant to your domain if being linked to the homepage." Within the webmaster tools, they rate your backlinks from one to five in a little green bar - the higher the green bar the higher the quality of the link in Bing's eyes. However they don't actually say whether these backlinks should be anchored or not. But all the evidence is that Bing is very keen on anchored backlinks.
Are you asking how long after you have an additional backlink does Bing recognize it? I would assume that has to do with the popularity and rank of the site linking to you.
In my own experiences, Bing would work just like other engines. Those hot and authority sites would usually have more frequent crawling and links would be pick up more promptly. Of course, a Ping service would also be helpful for this purpose. :)
all the best,
AS you do work on other search engine. same work process do in Bing too.