Ok so the trick to pesto is the type of basil you use. True pesto comes from Liguria and therefore you need Genovese basil. I would give you my recipe but I just eyeball it. I use basil (grown on my balcony in the middle of Milan), pine nuts, grana padano, extra virgin olive oil (my olive oil is actually also from Liguria but that's just a coincidence since we like the flavor) and a tiny bit of fresh garlic and salt.
The second trick is to freeze your food processor bowl. I actually use a mini chopper and I never freeze mine, but if you want cold pesto, you should freeze it first.
The thing with pesto is that you need to really do it to taste. When I used to live in the US, I could never find the right basil and my pesto always sucked. Also, it has to be organic basil bc that really changes the flavor of the pesto. Just add the ingredients a little bit at a time bc you don't want anything to overpower the basil.