Salvaging in EVE Online can be a lucrative career or just a good way to get some quick ISK. With a Salvager fitted to your ship, you can attempt to salvage usable parts from wrecked ships in space. Using these salvaged parts, you can manufacture rigs.
To salvage from a wrecked ship, you need to have the Salvaging skill trained to at least level 1, and you need to have a Salvager fitted on your ship.
The Salvaging skill has the following prerequisites:
Each level of the Salvaging skill increases the chance of a successful salvage per cycle of your Salvager module.
To use a Salvager, target a wrecked ship, remove any loot from the cargohold (it will automatically get put into a jetcan if you Salvage before looting), and then get at least 5,000 meters away from the wreck. Activate your Salvager module and wait for it to finish a cycle.
After the salvager finishes a cycle, you see one of three messages (these are paraphrased; I don't remember the exact wording of the messages):
If you get the third message, your cargo hold will now have the salvaged items in it. If you get the first message, you should let your Salvager continue to cycle until you have received the second or third message.
In general, Destroyers (like the Cormorant, Thrasher, Coercer, and Catalyst) are good for salvaging. They have fairly high sub-warp speed and a fairly large cargo hold. A fast ship can travel quickly from wreck to wreck, and a large cargo hold will ensure that you have room for the salvaged parts. Destroyers are also tough enough to destroy fairly powerful enemy ships. A Cruiser can also make a good salvaging ship, because it can handle tougher enemies and is still fairly fast at sub-warp.