Need advice on teaching methods "stay" and "down"

My little guy, Elric, is a pretty fast learner. The problem is that I'm not the best teacher

He knows how to sit and lie down, as well as "go potty", but I'm struggling with how to train everything else. My biggest problem as of now is "wait" or "stay" but I would also like him to learn "down" when he jumps up. The reason I need him to learn this is to hopefully eliminate his begging (as a smaller pup he wasn't interested in treats so I fed him a variety of people foods. Now whether your taking a drink of something or eating something as simple as a cracker, he tried to jump up and take it ). I am clicker training him, and he does pretty well, but whenever he sees me grab the clicker his energy level skyrockets. Even while practicing "sit" and "lie down", if he doesnt want to do it he will start barking and bouncing around. I don't reward him until he does what I ask, but I think teaching "down" will also help with this. Any advice on how to do this would be very much appreciated

You might have difficulty teaching "down" if you are already using the command "lie down". Maybe try "off" instead? Just to avoid any confusion.

When the dog is bouncing up we have found that by folding your arms and turning your back to the dog whilst using the command "off", works nicely. Essentially ignoring the "crazy" behaviour. Once the dog is no longer jumping up and is calm I then repeat the command and praise.

I am sure SmokeyBear will be able to provide you with more comprehensive advice.

I agree - 'off' is less confusing than 'down' to stop bouncing on people
One of the easiest ways to do that tho is to simply teach them what you want them to do - usually a nice 'sit' is good - mainly a dog cant jump and sit at the same time (OK my girl can but she is odd)
So as soon as you are in a situation where your dog would usually bounce reward them with a treat on the floor BEFORE they can bounce - then ask for a 'sit' and give lots of treats for sitting

as for 'stay'
I actually dont teach it at all - 'down' ot 'sit' or 'stand' means 'stay in that position till I ask for something else or you are released'
and it is the easiest thing in the world to teach

Get the dog in position and reward - reward 5 times in quick sucsession so they are basically chewing the whole time and dont even have the chance to move and get it wrong
Then release (I use 'OK) lure them or use your body laungage to make sure they move

Do the same again but 2 treats quick, pause 1s 2 treats quick - then release

Keep slowly building up the gaps between treats so the dog is waiting for a longer and longer time

They really get this pretty quickly - 'I just lie here and you feed me - OK'

Then build up some movement - move your hand slightly away from their face - then back really fast before they can get up
reward, release
Move hand slightly more, reward, move it less, reward - release

work to moving your hand away totaly, slowly standing up, slowly taking tiny steps away, steping to the side, walking round the dog, walking over his back, running, jumping about, droppping toys, treats, etc

Build everything up slowly a step at a time, if the dog gets up and moves you asked for too much too quickly

Thank you! I do also think that he was getting confused with the whole "down" and "lie down" bit so I'm sure "off" will work much better

As for teaching him to stay sitting until I release him, whenever he sees or smells his treats he gets very excited (which is understandable considering I get that way with some of my favorite treats) and bounces around alot. Even getting him to sit, which he is quite good at, is extremely difficult. Is there a training exercise I can do with him that will help to calm him down before we start working on the staying activity?

If using rewards it's important to show the dog an empty,flat hand as a stay signal. Not a closed one obviously holding a treat, as probably that's how you lured into position.
I don't use a stay command either.....but always reward with the word "Good Down, Good Sit" etc, so you enforce the action with the praise.

Kikopup and pamelamarxsen on Youtube are fab for training videos, it can help to watch someone else teach it rather than just read instructions

Jumping up
http://www.youtube.com/watch?v=C9utUCUAtVY
http://www.youtube.com/watch?v=lC_OKgQFgzw

Encouraging calm behaviour
http://www.youtube.com/watch?v=wesm2OpE_2c
http://www.youtube.com/watch?v=n4pxVA1JD3Q&feature=plcp

Impulse control
http://www.youtube.com/watch?v=TzM0nvlQPsY&feature=fvsr
http://www.youtube.com/watch?v=yJd3XceMxN0

^^^^ yup you can find anything with them

Puppy zen/leave it is a good thing to teach if your dog goes nuts for treats

Have a treat on your hand and every time they go towards the treat simply close your hand over
Dont move it away just dont let them get the treat - let them nibble, lick paw whatever but they get nothing
the sec they do anything that is not bug the hand with the food then mark it (with a click or say 'YES') and reward from your other hand
So your dog learns that its his choise - if he chooses to bug you then no treats, if he dosent fixate on the treat then he gets a treat

Thank you!!!