To Improve at Go, Study Professional Games
This is part of my "how to improve" advices.
What professional players to study?
I suggest that you just look over the games of several professional players, and see which one you like more. Once you chose one, get several game records from that particular player and study those games.
When I was an insei in Japan, I studied mostly the games of Takemiya Sensei- that's what my teacher recommended, in order to understand the use of influence. Other commonly recommended professional players are Honinbo Shusaku, Go Seigen, Takagawa, Otake.
How to study a professional Go game?
The hard way to study a game is to stop at each move and try to understand the reasons for it, and think what would you play next.
The easy way is to just replay the game and enjoy it in a light way.
There is also an intermediate way, which is to memorize many professional games: this doesn't require any analysis, and it provides better learning of shapes and direction of play compared to just replaying the game using the game record.
Either way, it is important to apply things you saw in the pro games you studied, in your own games: either the fuseki, or an invasion, or some shape.
I find it much more enjoyable to replay the games on a real goban, instead of replaying it in a SGF viewer software program. It is also much easier to stop and think at each move, while a SGF viewer encourages one to just click fast through the game.
Comments or no comments?
Comments are definitely useful, since it is impossible otherwise to understand what is going on in a top pro game.
I recommend though to first replay the game without comments, and just think about it for yourself; then replay it again, this time reading the comments.
How to get SGF files with Go game records?
In the "Go Software and Online Resources" I listed several ways to get your Go game records collection.
You can also use Google to find SGF files on the internet: search for filetype:sgf and it will return links to random free SGF files on the internet. You can add the name of a professional Go player to the search, for instance like this: Takemiya filetype:sgf.
How to get a printed game record?
Almost all SGF viewer software have a printing feature. If you don't have such a software program available, but you do have internet connection and a printer, you can use the free printing service from gobase.com.