Congratulations! Your dog should be behaving very well now, having mastered the basics (basic, yes, but tricks #1-10 are the most important things your dog can learn). Now, let's work on training your dog to properly interact with the world around him. One of the great things about dogs is their ability to help others, and being able to pick up dropped items or other objects is a very practical thing for dogs to do. In fact, assistance dogs are trained to do this very thing. Whether or not that is your goal, teaching your dog take it, is a very beneficial trick which we will build off of later on.
Step 1: Get one of your dog's favorite toys and set it on the ground. Wait for him to pick it up in his mouth. Click and treat. Step 2: Repeat this several times. When he starts picking up the toy without hesitation, start using the command take it when you click and treat. Step 3: After a few times of that, see if he will pick it up at your command! Step 4: See how many objects he'll pick up! Point to the sock and say, take it. Click and treat. Point to the remote and say take it, etc.
It wasn't hard to teach Caspian take it. I set down a toy he really loves, and waited to see what he would do. He looked around to figure out what was going on, and saw the toy there. He bent down to chew on it and I clicked and treated. I did this again, each time waiting a bit longer to teach him that I wanted him to keep it in his mouth until I clicked. After a while I started using the command take it when he got it right.
He gets frustrated and won't pick it up! Believe it or not, he may be getting frustrated because you are! Do your best to be patient and don't say anything. If your dog growls, ignore him. He'll eventually get it. If you need to, click for any behavior that is not quite but close to what you want (i.e., if he goes near the object or touches it). After that, you can eventually shape it into the behavior you want.
Tip: "Teaching your dog Take it now will pave the way for many great tricks later on!"