you must have a hook. it has to be something so catchy and that people will never forget. we've all had those songs that won't leave our heads, right? why? it doesn't automatically mean they're good. it means they're very well written. the right words meshed with the right melody.
the simpler, the better. sometimes we write a really good line, and then we want to cram it all into half a beat. you have to let your words & melody "breathe".
sometimes the words you write are influenced by how long the chorus or the verse is. it also goes the other way around.
would you believe i have songs from more than 15 years ago that i've left on the shelf? it's easier to write about something you've experienced, as well. so try to experience as much as you can without harming yourself and others.
it takes time to be fluent in this "language" as well. good songwriting is not something you learn overnight.
it may be helpful to disect songs which you think are well written. study them carefully. try to figure out what makes them catchy... find a common denominator - something that all those songs have.
aside from those things, i'd have to know which genre you want your songs to be. although standard songs usually have 3 parts: verse, chorus & bridge... A B & C. everything just expands from that.
one last thing. i read the word 'cheezy' in one of the other posts. i agree.
many songs use idioms, similes and metaphors. you can try those too. once you learn the basic guidelines, you'll know which ones to throw out.
hope that helps a bit.