When you set up your store you should aim to break down as much of your product as possible. During set up you will normally set these up as attributes, within an attribute set. You can then specify which of these fields will be searchable in the advanced search, a basic advanced search may look like this;
In this example, we are going to add fields to this search, in this case whether a suitcase is expandable or not.

How to make an attribute appear in the advanced search;
1. Navigate to  -> Catalogue -> Attributes -> Manage Attibutes
2. Find your attribute that you want to edit and click on it, this time it will be suitcase_expandable
3. On the front end properties section. Look for available in advanced search and change this to be Yes

4. Save the attribute and your attribute will now appear in your advanced search parameters.

The advanced search can help your customers dig deeper into a store with a lot of products, and in ecommerce giving the customer what they came for is the main aim of the game in magento ecommerce.