product rating website

Hii guys i need to start a project(website) product rating website!
I need to do a mysql design

I never have done big project mysql design

i need few tips on this !

Like what all tables might be required and stuff!

Project -> there will be various products like mobile,camera and etc..

Say user might rate each of the products features like say example
mobile nokia N75-> camera,battery,gsm etc..

How do define the properties for the mobile bcos 1 mobile might have feature which other does not have and when new feature is to be added , it must be made easy!

I will do the mysql design ! i dont want complete structure ! i want some tips and backbone of the mysql design !

re: product rating website

I started with it and make few tables

1. category -> stores different types of products i.e mobile,camera
2.sub_category -> like in mobile -> nokia,samsung
3.product_subc -> in nokia -> 3310,1100 etc
4.mobile_product_features -> here i am having problem

How to store the features of the mobile ..
a.make columns for each features available and store boolean values for each mobile(yes/no) for corresponding feature?

b. make a array of all the features of a mobile and serialize and store into Db?

later requirement : i must take in mind that later searching based on different features will also be done!

so which is the better option a/b or is there any other option also?