I've been bass fishing at a certain pond in Northern MD for 6 years now(I live walking distance from it.)  I have caught hundreds of bass from it but recently bass have been harder to catch.  

Switch it up some, variety never hurts. A little more info on your spot would be helpful, like vegetation, structure, water clarity, depth, etc.

Just switch it up.

If you been using the same method over and over, they may have become conditioned to it. Try a jig or something different.

I would try that "Walking Worm" thing you were asking about in Fishing Lures and Baits.

The pond has some vegetation but not too much, the structure is mainly fallen trees, the water is mildly clear to slightly murky(I can see the bottom in 3 ft of water in most places), the deepest is 15 foot. I have tried a lot of items in my tackle with no success. Any specific things I should try?

Perhaps try a faster presentation like a swimming worm or a jig worm . A wacky worms is a finesse tactic and generally fished really slow giving the fish plenty of time to see it.

You definitely should try different approaches like mentioned above but another thing to consider is that they (bass) might not be there anymore. Fish die...people take them...it happens. The lake i've fished has slowly declined in population from winter kills. If it's not properly maintained it's pretty difficult for it to bounce back in population, especially if there is consistent fishing pressure on it every year.

Try swim baits, like hollow body from Berkley or Yum. You can straight retrieve it, pump it like its dying, burn it like its fleeing from predator...it's a great way to fish and will catch more than just the bass. Good luck trick.

use diffrent approaches meaning presentations and baits -God Bless