A precaution is something you do to protect yourself or someone/something else before something happens. Like, if you know you always spill milk when you pour it, you hold it over the sink. Doing that is a precaution. A considereation is thinking about something. It doesn't mean that you have any actions at all. You might say to yourself, "wow, I usually spill milk if I pour it" You don't have to act on what you have thought.