Database design for an online babyShop ,Toy shop
Your design commonly looks good except few mistakes.

1) You had used a wrong field in order to establish a relation between ProductCategory and Product. You have to use ProductCategoryID in Product table instead of using ProductCategoryName. Howeever, some products may belong to more than one product category.
If this is a valid case for your project, you should add additional table something like "ProductVsProductCategory" which will allow you to establish a "many to many" relation between Product and ProductCategory tables if you intend to add some products into multiple categories.

Basic structure of ProductVsProductCategory might look like following:

ProductVsProductCategoryID (primary key)

ProductID (refers to Product table)

ProductCategoryID (refers to ProductCategory table)

2) OrderProductName field in the OrderDetail table is unnecessary. You have a relation to Produt table and you can access ProductName from there anyway. You can cancel it.

3) OrderNumber in the Order table is unnecessary if it is not a special value rather than unique identity number. You can use OrderID field as an identity of the order.

4) Similary, OrderQuantity and OrderTotalPrice fields might be unnecessary if you have not special reason to place them there. You can calculate order quantity and total price values by means of using basic sql statements that sums related OrderDetail rows.

There are many additional tables can be added depending on your project requirements. I also recommend you to follow MSDN articles and specially CodeProject in order to improve your abstraction skills.