Low leakage and electrolytic capacitor don't really go together, but given that leakage goes up with temperature, capacitance and percent of rated voltage applied, you can obviously arrange circuit conditions - if not environmental - in your favor: use the smallest capacitance with the highest voltage rating possible. Also possibly relevant is that the aluminum oxide dielectric tends to degrade after some time (undefined) without a bias voltage applied, so leakage tends to be highest in the first few seconds to minutes after voltage is reapplied.
Other than that, consider a different dielectric is minimizing leakage is really important.