Following the example of others works in many cases when it comes to self-improvement. There are no doubt at least a few people you've crossed paths with that left a heft impression on you, whether through their talents, charms or unique qualities. Think about what made these people so likeable and memorable. Do you see any of their traits in yourself? Whether you do or don't, these examples are a good model to start with. Everyone is different, and everyone has something unique to offer. If you can pinpoint what makes you special, highlighting those best traits of yourself in your behaviour will make you stand out in peoples' minds. Are you funny, smart, charming, fashionable? Knowing where you stand realistically and knowing how to emphasize those best traits will make you more memorable in the eyes of others. The most memorable people are usually only remembered for one or two things. Only closer friends will have time to see you for who you really are. If you're intent on making a big impression with someone, you should focus on emphasizing one or two of your boldest qualities. If you try to look at a situation through someone else's eyes, you'll be that much closer towards knowing exactly how to act and leave a good impression on them. This is especially helpful if you already know the person you'd like to impress. By knowing them, you'll be able to tap into their train of thought more easily. Even if you don't know the person personally, any fact you know about someone can help in predicting what they'll look for in you. For instance, most prospective employers will be looking for a lot of the same things: punctuality, politeness and professionalism. Why do you want to make a good impression? Asking for a specific reason why may seem like an unnecessary question, but taking the time to consider the reasons why will help you decide how you'd like to be memorable. If you want to make a good impression on someone you're not planning on having a close friendship with, you can rely purely on surface charm. A more enduring connection (like a new romantic partner) may be worth letting see your true colours. There's nothing wrong with putting on a mask for other people, just as there's nothing wrong with truly being yourself. It all depends on the intent you have in mind.

Summary:
Reflect on people that made an impression on you. Consider what you bring to the table. See things from other peoples' perspectives. Decide what your goal is.