Assuming you don’t have another game or don't have any friends to help you get a Scizzor there are 2 ways you can use to increase your chances at getting a Scizzor. You can use bug or steel type affinity tickets to substantially increase your chances of getting a Scizzor. Currently the only way to get these is 50 or 250 moves of the same type you as the affinity ticket you desire. Keep in mind these methods are non renewable and there currently isn’t a renewable way to get affinity tickets.
The other way is kinda niche and not likely to ever be relevant. Anyway occasionally there are special limited time recruitment things that give you a very limited list of Pokemon. At the time of this post there has only been one of these (I can’t remember what it was called). If Scizzor does show up in one of these in the future it would be an incredibly easy way to get a Scizzor.
Not exactly a way of increasing rates but still worth mentioning is the fact that there are events that contain free Pokemon from time to time in addition to the season pass and both of these could contain a Scizzor though like option 2 it’s incredibly unlikely that Scizzor will ever be given away like this.
