Choose a topic. Pick a subject that you feel passionately about, whether it's racism, war or women's rights. Look to famous political songs for inspiration. For example, the song "Fortunate Son" by Credence Clearwater Revival dealt with the fact that poor boys went to war in Vietnam while rich boys avoided the draft.
Settle on a lyrical approach. A political song's lyrics can be an upbeat, positively charged sing-along, like the anti-war "Lay Down (Candles In The Wind) by Melanie, funny, like those in Jib-Jab's video parody of "This Land Is Your Land" or they can be an allegory like "Strange Fruit," a haunting song about racial lynchings made famous by Billie Holiday.
Wrap your political sentiment in a catchy hook. All popular political songs attract listeners first by a catchy melody, hook or beat. Pete Seeger's "If I Had A Hammer" and "Where Have All The Flowers Gone" have infectious choruses that still make people sing along.
Express appropriate emotion. Infuse your song with righteous anger and heartfelt tales of injustice. Write lyrics based on true stories of social injustice and combine it with powerful vocals.
Write for your target market. Some political songs cater to the folk music protest crowd, others have more mainstream musical arrangements and subtle lyrics can be released as part of a pop music CD.