Hi Neha,
So basically you looking for a method to carry a research on shopping malls where you have to rank them.Now here you have just given a rough idea as to what you actually wish do to.When you say you have to rank the malls,there are various parameters on which you can evaluate a shopping mall.
First work out on the primary data,like the location,the variety of shopping it provides,the entertainment zones.etc.The usp one has over the other and whether its capable of attracting a huge crowd on the weekends and an appreciable one on usual days aswell.Make a comparative analysis of the first hand data.
In the second stage you can work more on the statistical part,i.e.what amount of sales it makes overall,the genuine sales which it makes,the profit & turnover it has.etc.You may not be able to find the hardcore figures but an approximation will serve your purpose.After this you can work on the perception of the walk-inns of the malls.Take a sample base of more than 100visitors randomly as the total population is unknown in this case.Set a hpothesis.Make a questionnaire which can be evaluated on scientific techniques.Ask the visitors about the benefits,purpose,purchases,point of attraction and various other attributes of the mall.Make a priority ranking of these parameters,as there are chances of many reasons associated to one.Try to find out the popularity of a mall amongst the visitors.Do a SPSS testing of the sample.And there are various techniques to test the secondary data from the field.Follow the one which best suits your purpose.Do this for each mall and you will start getting results as you will pass through stages.
Structure your Research pattern well.Set a obective for it.And try and collect huge data if possible as it will help you to give better conclusion.
ALL THE BEST!!