If you don't know whether you're employing the right word, then double-check by using a dictionary. So far so obvious, but what if you don't know you've got the wrong word?
I suggest a short-term strategy and a long-term one.
The short-term strategy for getting the right word
The short term strategy is do do the following test. If you think you are being very erudite by using a particular word, ask yourself if you have ever seen it used that way elsewhere. If the answer is "no", then it would be good to take a moment to check the word's meaning. After all, it could be that you are being strikingly original -- but it could also be that you are completely wrong.
The effect of using an obviously-wrong word (that is, obvious to everyone else) is that it makes you look pretty un-erudite. For instance, I once saw a reference to the "sentient facts". The word "sentient" means able to feel sensations. I have never come across a fact that had such an ability. I imagine that the writer meant "salient".
The long-term strategy for getting the right word
The long-term or ongoing strategy comprises the following elements:
- Read a lot.
- Read a variety of texts, not just those in your genre, and not just either books or magazines or newspapers or anything else, but all of them. (A typical feature article is structured in the opposite way to a news article, to take just one example.)
- Buy some reference books.
- Read them occasionally.
- Subscribe to, and listen to, The Grammar Girl podcast. This, the work of Mignon Fogarty, considers what words and phrases mean and how they should be used. It has several things going for it:
- First, it's short.
- Second, it isn't full of jingles and other nonsense.
- Third, it's accurate.
- Fourth, Mignon draws distinctions between American usage and British usage, where they differ.
- Finally, read my article about online dictionaries, and subscribe to or bookmark at least one of them.