I was reading through a few articles about D&D and one of the articles had questions about how to handle being a new DM. The question to the blog ended with the statement "There can be no heroes where there is no doubt", which is a powerful statement. If you want your character to be heroic or villainous (depending on the alignment of your campaign)there should be some level of doubt in your actions.
Are the actions that you are attempting going to create problems down the line for the overall plan? Is your current action going to cause your character to potentially die? In any action, there should be some level of weighing the risk versus the reward. Will your choice to stand and fight with low HP rather than fleeing and returning hold a greater reward? Does that matter to your character? Character development is important in determining factors like this. Some characters will be more likely to enter a situation if it will make for a good story, while some will enter them if the potential for wealth/power comes with it.
Regardless of what actions you take, thinking like your character will help you roleplay better and will result in your character becoming more of a memorable figure. I have found that the characters I remember the most about aren't necessarily the one's I've experienced the most with, but the ones that I have tried to roleplay best based on that character's development.