I've been asked to say how to avoid pleonasm. Bit of a poser that, because I didn't know what it meant.
Dictionary says: "The use of more words than are needed to give the sense (eg see with one's eyes)." A bit like tautology (which I had heard of): "the saying of the same thing twice over in different words (eg arrived one after the other in succession)." It also means "a statement that is necessarily true". Pleonasm is given as one of the synonyms.
For the writer, this is the curse of loving words. At least that's my take. We like the sounds and rhythms, don't we? We want to use descriptive prose to make our point. Is it the hidden poet inside us?
Trouble is, the more flowery the language, the more your meaning is obscured. That doesn't mean you can't use metaphor and simile and all the other wonderful tools which make up the richness of our language. But - here it comes again - you have to use them sparingly or you lose the effect. Your reader gets so caught up in the language, they don't hear what you're saying.
However, don't be deterred by the oft-quoted Johnson to "strike it out" when you write something "you think particularly fine". It was advice he gave to one person he thought was a terrible writer and it was meant to be sarcastic. Unfortunately it's been touted ever since to much put-upon writers as gospel from the master's mouth.
There's nothing wrong with discovering that you've put something really well. Good for you - you're improving. The warning - if you're going to avoid the dreaded pleonasm and tautology - is to write what you mean. Don't write to impress. Say it as simply as you can. Write spare.
If I have to reach for the dictionary to check a word, I assume my readers will too. If I find myself hunting through the thesaurus to find a better way to say something, I instruct myself to put in the first word I thought of. The thesaurus is to help you avoid too much repetition of the same word. Or to find something more telling. It's not to find something more clever.
Don't be clever. Be clear. Then you won't go far wrong, and you'll avoid saying the same thing twice.