Add a little Dijon mustard for a little more tang!
I like to add a little pickle juice to mine if it gets too thick.
If dill pickles aren't your thing, try sweet relish.
If you don't have fresh lemon you can use bottled lemon juice.
Fresh dill weed is best but if you don't have any feel free to use dried dill. Just use about half the amount.
If you like yours spicy, add a dash of hot sauce!
Minced onion is also a great addition to add even more flavor!