As we all know keywords having brand name have too much competitions and there are many website on internet that are using same brand name or keywords. Then how can a person do SEO with these keywords to rank a position among other website with same brand like keywords?
Try long tail keywords and your original keywords boost automatically. No doubt its a long procedure but effective. Apply co-citation technique.
The best thing in this regard is that you should go for general keywords for these brands, for example if your website is selling all top men's wear brands like Louis Philips, John Player, Peter England, Arrow etc then "Branded Apparels" is a generalized keyword for this. Think a keyword which is in mind of people rather than actual brand name as in the above case one is looking for a branded apparels rather than actual Arrow shirt one can get a varity of branded shirts if he/she goes this way.
You can do off-page seo like directory submissions, social bookmarkings, blog commentings, forums, etc. and do social media optimizations on facebook, twitter, linkedin, etc...