An easy way to promote products throughout your catalog is to establish relationships between products. The options available are: Up-sell products, Related products, and Cross-sell products.
Related products are meant to be purchased in addition to the item the customer is viewing. They compliment, enhance, or add optional features to the product.
Up-sell products are items that are similar, but are perhaps of a higher-quality, more popular, or have a better profit margin than the item the customer is considering.
Cross-sell products are offered on the shopping cart page as last-minute purchases before the checkout process begins.