*based on personal results
Step 1 - Start dropping hints
By dropping really obvious hints to your parents over the course of time, it will help "ease" them into the notion that their daughter likes to eat pussy. Make comments about women on TV: "Wow, Angelina Jolie looks smokin' hot in that low-cut dress" or "What I wouldn't give to meet Ellen Degeneres, she's pretty much my hero" or "Ann Coulter is totally a repressed dyke in disguise". Dropping hints like these on a regular basis might give your parents an inclination that your refusal to wear dresses is more than just bad fashion sense.
Step 2 - Stop hanging out with guys
This is vitally important especially if you just came out and you constantly find yourself surrounded by all your guy friends that are still praying that you might not be gay. Tell them all you've become an angry man-hating lesbian and it would compromise your look and cramp your style if you were to be seen with them. Ever.
Step 3 - Start hanging out with only gay women
Juxtapose to Step 2, it is vitally important that after you ditch all your guy friends, you only hang around with women. It's a plus if they are all gay too. Start bringing all your new girl friends over to your parents house. Make sure they come and stay for many hours; it's better to hide up in your bedroom like you're being very secretive. You can even pick one friend to bring over on the holidays (instead of a boyfriend). Extra points will be scored if you're secretly dating the girl that gets to come to all your family's holiday parties. Subtle flirting in front of family members with the "friend" will really make them sit and scratch their heads in wonder.
Step 4 - Pick a date
Don't just tell yourself, "Ok I'll tell them next week". Actually pick a date, and if you can pick a time, even better. Pencil it in on your calendar; "June 14, 2007 at 8:52 PM EST".
Make sure to tell all your friends in case emergency back-up is needed. You might even want to have someone waiting around the corner with the car running on the big day (except with these easy-to-follow step-by-step instructions that should not be necessary).
Step 5 - Practice, practice, practice!
Everyone knows that practice makes perfect. Write a monologue of your story to tell your parents; make sure to include why you are a lesbian and why you have chosen this moment to come out to them. Include lots of hand gestures and overly exerted facial expressions to help your monologue become really animated.
If you can, incorporate humor into your speech.
Think of yourself as the next Hollywood actress working her way up to an Oscar. I would recommend practicing in front of the mirror first, and work your way up to your friends. Ask them to role-play; you tell your coming out story and have your friends pretend to be your parents. If you can bring tears to the eyes of your audience than you know you've won them over.
Step 6 - Prepare your body
On the night before coming out, I recommend eating a nutritious pasta dinner so you can bulk up on high energy carbs.
Get a good night's sleep and wear an outfit that makes you look the skinniest. With a good night's rest, fantastic outfit and an overabundance of energy, you should be all ready to go. Give that monologue a few more practice runs in front of the mirror and make sure to use positive reinforcement on yourself; "You can do it! You can do it!". This will really hammer home that fact that you are a super, awesome lesbian who can conquer the world.
Step 7 - Location, location, location!
It's all about location when you come out to your parents.
You don't want to do it in the morning, because it could potentially ruin your whole day.
You don't want to do it during the weekday because your parents could be tired and cranky from a long workweek.
I would not recommend coming out in your house, because privacy will allow them to really let you know how they feel.
The best place would a popular restaurant; make plans with your parents to go out to eat sometime over the weekend.
Tell them you have some really great news that you want to celebrate over dinner. This will build up their excitement and put them in a great mood. As far as the restaurant goes, I might recommend someplace where you can inconspicuously consume large quantities of alcohol (like a Mexican restaurant). When you get there, immediately order 2-3 pitchers of Margharitas "on you" to celebrate the occasion. When they start asking what this is all about, tell them they have to wait until dinner. Go ahead and order an appetizer, keep their margharita glasses full and the talk light.
Step 8 - Game time
When the meals have arrived and your parents are three sheets to the wind, you should utilize that time to really unleash your powers. Preface your monologue with a great joke, maybe one that is slightly offensive but brilliant; I recommend something by Sarah Silverman. Once they start laughing, break into your monologue with passion they will certainly bombard you with stupid remarks or boring lectures. Make sure to time your conclusion with the passing of your server; as soon as your monologue finishes, grab your server's attention and request a dessert menu, than proceed to the most crucial (and final) step.
Step 9 - Excuse yourself to the ladies room
While the dessert menu is being placed on the table, excuse yourself to the ladies room and exit the table promptly leaving your stunned parents up to the devices of the server. Wait in the bathroom for 5 minutes, then return to the table. Watch your parents as they attempt to regain their composer in a public place, this will force them to accept you or atleast pretend to while in the company of strangers. If they do accept you, than that is great and you can go home happy knowing that you achieved success. If it doesn't work even after adhering to my Eight Step Program, at least you can take their drunk-asses home and hope they'll wake up with a hangover and a foggy memory of their night at the Mexican restaurant.
Good luck and let me know how it goes.