I think i can post again and thanks a lot to Kent.
While going through some articles, I realized contrast in typeface is very important but i can not find factors of design which affect the contrast. What are the factors that affect contrast? Is it x height, thickness of stroke or anything else?
Also to improve legibility, some people are designing fonts with tapered edges( called flaring and expansion of edges in a specimen). Does this really affect the legibility? and if it does any other points that can affect legibility.