The discovery of New Physics, using weak decays of mesons is difficult due to intractable strong interaction effects needed to describe it. We show how the multitude of "related observables" obtained from B\to K^* \ell^+\ell^-, can provide many new "clean tests" of the Standard Model. The hallmark of these tests is that several of them are independent of the unknown form factors required to describe the decay using heavy quark effective theory. We derive a relation between observables that is free of form factors and Wilson coefficients, the violation of which will be an unambiguous signal of New Physics. We also derive other relations between observables and form factors that are independent of Wilson coefficients and enable verification of hadronic estimates. We find that the allowed parameter space for observables is very tightly constrained in Standard Model, thereby providing clean signals of New Physics. The relations derived will provide unambiguous signals of New Physics if it contributes to these decays.