How to design database for market place website
My approach would be to think in terms of objects. Like John Eisbrener mentioned, think of the types of products that would share common attributes, like model number, weight, ISBN, and so on. But also think of the people that would be involved. A vendor table can list the people selling, and a customers table would list the people buying.

As far as a best practice that I try to live by is don't repeat your data. A table recording a sale should not include a customer's delivery address, that should be referenced through the customers table by using a foreign key constraint. But most of all open up a program like Visio and start with the basic information tables you pretty much know you'll need, and build it out. It's much easier to make changes there than altering tables later