Once you begin spending some time streamer fishing, it's easy to see that the way you retrieve your streamer plays a huge part in how successful your day of fishing will or won't be. Water conditions, available food in the water, and the preference of the local fish all play a huge part in which streamer retrieve will mean more fish in the net. Across the board, one technique of retrieval may not necessarily be better than the other day in and day out. Instead, it's best to have a handle on the variety of techniques at your disposal and see which one works best on that particular day.
A retrieve simply means the rate at which you strip line back toward you as you actively fish a streamer. The retrieve can also mean the actual amount of line that you pull toward you as you fish. There are a few basic retrieves you should have in your book of tricks to try out on the water and see which the fish prefer.
The two main ways of streamer fishing are stripping and swinging the fly. Each style has its own respective place and use, but don't be afraid to try new things. Swinging a fly on a tight line and adding a few irregular jerky strips here and there throughout the drift can be a really good way to get into some fish.
Swinging the fly is the preferred method for salmon and steelhead fishing. It even works well in rivers for striped bass. Steelhead and salmon respond to a swung fly with more aggression than a stripped fly. In very cold winter and spring water, a swung fly is a great way to get into trout that are locked on the bottom but can't resist a big meal. They are far less likely to chase a streamer when their metabolism is low, but may not refuse one that's directly swung in front of them.
As a general rule:
Whichever retrieve you prefer, it's good to know and have experience with a variety of retrieval techniques. You never know which one is going to be the ticket that day. No one technique is universally better than the other, but one technique may be better suited to the specific conditions that day. It's easy to change and try a whole bunch of retrieve styles while fishing, so mix it up and try them all. You never know which one will be the best until a fish responds by eating your fly!