What are some things that make you look "pro" at specific video games? It doesn't mean you have to necessarily be pro, but it needs to be visually impressive but perhaps not that hard to pull off.
Example. Super Mario Bros.
Most people just jump on two goombas one after another to get 300 points (100 pts first goomba, 200 pts second one). But if you instead land a single jump right in the middle of two goombas just right it looks hella impressive and you get 500 points (100 pts first goomba, 400 pts second one). And all you really have to do is wait for a goomba to hit an obstacle (such as a pipe) and reverse direction before you land your hit (exception of 1-2 where there's a "gimme" right at the start that everyone can do).
I'm going to mention the 1-UP trick not because it's a good example of looking pro but because if I don't mention it then someone else probably will. The reason this isn't a good example is it's too overdone and almost anyone can pull that one off. It would have made you look pro back in the day before it was widespread knowledge though.
Here's a counter-example -- something that is pro but which doesn't look pro. Getting 15 coins from a coin box, particularly if you can do it a few times. Only reason it doesn't look pro is people watching you play are likely not counting while doing so. 15 is the most coins you can get from a coin box. 13 is pretty typical. 14 is the best you'll usually do if your timing is very good. It's all about that perfect timing because once you hit it the first time an internal clock goes off and you only have that much time to milk the rest before it'll only give 1 coin.
Also naturally if you get a 6 as the final digit on your timer on all non-Bowser levels that's going to look extremely pro, but that actually is difficult to pull off, whereas the goombas thing isn't.