If you have a tricky serve that opponents miss or pop up over and over, that's great. However, too much reliance on this can actually hold you back. The same tricky serve that your peers mess up against might be returned more easily by stronger players, including the ones you hope to learn to beat. For example, if you have a side-top serve that many opponents push back and so pop up, stronger players, especially after they see the serve a few times, might just drive or loop it, and suddenly your serve is a disadvantage. So instead of relying on winning off the tricky serve over and over, develop a good third-ball serve, one that players at nearly all levels will return somewhat passively, allowing you to attack. Then you can use the tricky serve as a highly effective variation that even stronger players might never adjust to.
Your typical third-ball serve is a short and low backspin or side-backspin, which is often pushed back, setting you up to loop (or in some cases, a regular drive). The irony is that if you do these serves well, opponents will tend to expect backspin, and so when you fake backspin but instead give side-top or no-spin (by contacting the ball near the base of the paddle but still exaggerating the serve motion), the opponent will often push and pop the ball up. Sometimes the no-spin becomes the main serve, with spin the variation, since no-spin serves are harder to push heavy or drop short than backspin, and if very low, are often harder to attack as well.