The way I remember it is considering Lithium. Lithium is a VERY strong reducing agent. What does reducing agent mean? It means it gives an electron away. Consider Lithium - one valence electron, so it's prone to giving it away to form a complete outer shell.
It's electrode potential is -3.04V. Remember that electrode potentials are, in truth, standard REDUCTION potentials - they are the potential energy of REDUCTION so it's half equation is written as a Lithium cation gaining an electron. The negative value suggests it isn't a favourable process, so the opposite way around is very favourable - it's far more favourable for elemental Lithium to lose it's electron (E = +3.04 V).