well i'm not an expert in this topic but i have written 4 songs i have like 2 weeks since i wrote my first one and i try to use the basic ways like verse,chorus,verse,chorus,bridge,solo,verse and outro
and i try to first have a rythm in mind and then get it in my guitar and then write it i guess i still need more practice in this it's tough sometimes it took me like an hour to write one song