You have been with your boyfriend for quite some time. And now the time has come to ... *drum roll please* ... meet his parents! Like in job interviews, you want to be prepared when you meet the mother and/or father of your boo. Why? Because [1] you want to set a good impression for your "maybe" future in-laws; [2] some boys tend to be "mama's boy" and if that's the case, you want to show his mother that his boy is in good hands, even on the first meet up; and [3] for whatever practical reason having a good relationship with your BF's parents would bring.
There are three things that I would like you to keep in mind when this opportunity comes: Information, Appearance, and Attitude.
INFORMATION
You would not want surprises or awkward situations so do your research! Ask your boyfriend what his parents are like. Are they jolly, serious, strict, friendly, etc so you would know how to adjust. Check their photos so you would be familiar how they look like.You may also want to know how to address them. Would they prefer to be called "Tito/Tita", "Uncle/Aunt", sir/ma'am, possibly "Papa/Mama" or maybe first name basis. Knowing their backgrounds would also give you hints for conversation topics, or gift ideas if you plan of giving some.
APPEARANCE
When we say "first impression", it starts at the moment their eyes lay on you. So dress in a way that is acceptable to many. It may be conservatively, but be sure to add your own flavor. Some parents may not like it when a girl wears cleavage-showing tops, mini-skirts, see-through clothes, too much make-up or jewelries. Again, asking your partner won't hurt so consider it as well.
ATTITUDE
This is very important as the way you carry yourself, how you think and respond would truly define the kind of person you are. Do not worry much or overthink; instead, be cool and stay natural. As long as you are sincere and true to yourself, this would reflect in your aura which the people around you would also notice. Create a positive atmosphere by always smiling. Give your attention and maintain eye contact when having conversations. And of course, be courteous all the time!
If you sense a positive feedback after the meet-up,well you did great sis! But prove that this is not just a show and maintain the relationship for the next meet-ups. If you feel things don't turn out well, don't fret as this is not your first and last encounter. You can still correct mistakes, or improve how you present yourself. Usually, the first meet up is the most awkward as you or the parents, or both of you would be more of observing or feeling each other, rather than interacting. The upcoming meetings should be more comfortable. But if even after a few more attempts you can't still win their hearts, it's okay honey! You did your best and you're not getting married with your boyfriend anytime soon so you won't have to deal with his parents that much, anyway.