#1 - Avoid Tricks With Distinctive Props
If all you need to do to find out how a trick works is google the main props and the word "magic" that's not a great trick for the 21st century magician.
Of all the reasons not to do the Bill in Lemon trick, you can add the fact that the first thing someone would google is: bill lemon magic.
#2 - If You Must Do Those Tricks, Modify the Props So They're Unique To You
Ok, you just have to do a Bill in Lemon style effect. Well, let's switch out the props. Let's use an orange instead of a lemon. That shouldn't be a problem as it still has the properties we need for the trick. And instead of a bill use... I don't know... anything you want. A giant fortune-cookie fortune. Whatever.
You offer your spectator a choice of a dozen fortunes. Each are (conveniently) on a dollar bill sized piece of paper. They choose one and sign it. You say that you were hired by the Chinese Food Association of America to make a healthier alternative to Fortune Cookies, so you created a way to get a fortune inside an orange. They pick an orange from a bowl, you cut it open and inside is their signed fortune.
Is this a good trick? I don't know. I'd give it a C-. But it's at least better than "I MADE A DOLLAR GO TO A LEMON FOR NO REASON!" Which is the standard presentation.
And it has the added benefit that if someone searches: orange "fortune cookie" magic, they come up empty.
#3 - Recontextualize Effects
You don't have to change the props. You can also redefine what the effect is. An example from this blog is Cryptophasia. What is, essentially, the effect of a magician predicting a spectator's freely named number was changed into a spectator being able to interpret a language he didn't think he knew. The other two phases of the effect recontextualize two other classics of magic/mentalism.
How about ambitious card. If you do four phases and talk about how the card always "rises to the top." It doesn't take much for someone to google the method to make the card rise to the top. So what if, instead, you said the card was drawn to the palm of your hand. And, in fact, this was some new type of "super-palming." "I can actually palm the card through half of the deck." Now you draw the card to the top a couple times. Draw it to the bottom once. Draw it to the top with a bend so they can see it this time. And then you say, "Even if I put my hand in my pocket the card is still drawn to it." The spectator pushes (what they believe to be) their card into the deck and you remove your hand from your pocket, there's nothing in it. You empty out your pocket, but no card. "Huh," you say. You poke through the items that were in your pocket, eventually opening up your wallet and finding the card stuck in there. "I haven't perfected the technique," you say.
Again, this is just an idea I'm making up as I type. But it's a little more interesting than "the card rises to the top." (It also justifies the card to wallet some people end an ambitious card routine with.) And it allows you to perform one of the most classic effects in card magic with no trail to be found online. If they start googling "card drawn to hand" or "superpalming" they'll find nothing.
Well... now they'll find this post. Sorry bro.
#4 Combine Effects
By combining two effects you may be able to blur the line of what each individual effect is. Thus making it harder to google.
The two effects mentioned above—Cryptophasia and the Ambitious Card presentation—would also be examples of that. Another is the previous post, All Seeing Eye of the Beholder.
#5 Overwhelm Them With Possibilities
The previous ideas have looked at ways to make your performances more unique and thus less googleable. But you can go the opposite way as well. If you do a poker routine or a routine where coins change, these effects are so generic that anyone googling will just be overwhelmed with avenues to explore and won't be able to find that specific coin change or poker routine.
#6 Don't Buy the Latest Big Thing
Sorry Penguin and Ellusionist. I love you, but you're just too good at marketing. Many of the effects you release, and really get behind, end up overexposed. Not only that, but a good portion of your customer base are the most pube-less members of the magic community. And so you have a lot of shifty 12-year-olds uploading videos of themselves performing the latests sensation in their dull monotone to youtube. So not only can your audience quickly discover that your little miracle is available to anyone with $15 dollars. They can immediately learn how it's done via some kid's poor performance which serves as an explanation.
#7 Get Your Material From Books
This is the flip-side of #6. I don't want to sound like Grandpa Jerx here, but there is so much good material in books that there is no record of online.
Honestly, I'm as guilty of eschewing effects found solely in books as anybody. I will overlook an effect in a book for years and then hop on it once it's released as its own instant download. I know it's lazy on my part, but sometimes it takes someone really shining a spotlight on an effect for me to give it the attention it deserves.
So do as I say, not as I do with this one. If you're looking for material with no online paper-trail, look to books.
#8 Remove Yourself From the Magic
This has been a theme of this site since the beginning. The most tolerable and enjoyable amateur, informal magic presentations are the ones that aren't centered around your ego. They're the ones where you shift the focus off yourself and let the audience put as much of the focus back on you as they choose to.
This style won't necessarily make your effects un-googleable, but it will make them less likely to be googled. It pulls the rug out from under the 10% a-holes I mentioned above. Their compulsion to "expose" you goes away almost completely when you're not looking for credit or validation.
If this post has its detractors it will be people saying, "Oh, come on. You're worried about a few people googling a trick and finding out... that it's a trick? As you said, they already know that, so who cares? It's all a bit of fun. You're taking it way too seriously. Isn't your ego the thing that is dictating you scramble to make all your material seem original and not traceable on Google?"
So let me preemptively say no, that's not what this is about. I don't want an effect to be un-googleable for my sake. It's for the sake of the person I perform for. I want them to feel the experience we just had isn't some cookie-cutter thing that comes in a box.
Have you ever watched Dr. Phil when he has some older woman on who's involved in some Nigerian catfish scam? She's always a hefty woman in her late 60s who thinks she's talking to some handsome silver fox across the sea who is perpetually just days away from visiting her. She's about $200,000 in at this point (but he's assured her she'll get it back). Dr. Phil will read some of these love-letters the guy has sent the woman and she will just be beaming at how romantic they are and how special they make her feel. Then Dr. Phil plugs the love-letters into Google and he shows her 100s of results for the same email and you can see her crumble inside. I think, on a much smaller level, some spectators can have a similar letdown when they realize this is just a "routine" and not a genuine rare moment.
You want your spectators to feel like what just occurred was unusual in some way. You want every performance to be a little love-letter to your audience that hasn't been sent 1000 times already. And it turns out the best way to do this is to actually strive to make something unique. If you look at those steps above, that's what most are designed to do. That's why, if an electromagnetic bomb takes out the internet tomorrow and you don't need to worry about people googling anything, it's still a good idea to follow many of the suggestions above.