You contemplate taking your dog for a walk with mixed emotions. You love the idea of going for a companionable stroll through the neighborhood together, but when you pick up his leash he becomes the Tasmanian Devil.
Here are suggestions for turning this potential disaster into the enjoyable outing you dream of. Exercise first. Spend 15-20 minutes tossing a ball for your dog in the backyard, or providing intense mental exercise with a heavy duty shaping session. You'll take the edge off his excitement, reduce his energy level, and make leashing-up and walking more relaxed and enjoyable for both of you.
Pick up his leash throughout the day. He gets amped up when you touch his leash because it always means the two of you are going for a walk. If you pick up his leash numerous times throughout the day, sometimes draping it over your neck and wearing it for a while, sometimes carrying it from room to room, sometimes picking it up and putting it back down, the leash will no longer be a reliable predictor of walks, and he won't have any reason to get all excited about it.
If, when you pick up the leash, he goes bonkers (the behavior you don't want), say "Oops" or "Too Bad" in a cheerful tone of voice (what's known as a "no reward marker," it simply tells him no reward is forthcoming), set the leash down, and walk away. When he settles down, pick the leash up again. You're teaching him that getting excited makes the opportunity for a walk go away; staying calm makes walks happen.