I bent down to suck on her lips
Spread wide did my hands her hips
As i move her closer
My tongue did propose her

Quote by RuthieI never said it was simple. It isn't to me anyway, because English isn't my first language.
I try to go by the accepted spelling in the writer's own country. Words like colour, harbour, as opposed to color or harbor, and the ise vs. ize endings of words. I am American, though, and my instinctive spelling is US English. If I don't recognize the spelling of a word, I try to find a reference to it being spelled that way, if I can't, I change it to American spelling. What we want is consistency in a story. If you use the spelling colour, you shouldn't spell realise with a z, and vice versa, of course. The main thing we try to prevent is inconsistent spelling. "I went to the harbor today, and the colour of the sea made me realize that I needed to organise my paint box." Some verbs always end in ise, of course, no matter which side of the Atlantic you're on. There are also some American words, such as analyze, that always end in yze.
It's not always as simple as it seems.