It is advised to use this over the walkthrough at erogedownload.com, as that one has multiple inaccuracies and is now outdated.
Anyway, on this page is a flowchart guide for achieveing 100% completion in the Steins;Gate visual novel. The text on this flowchart completely matches with the official JAST translation and has been tested, so there should be no problems. If by chance problems do arise, leave a comment below.
Even if you don't want to use a flowchart for your first readthrough of the VN, it would be a good idea to read the About page to the right, as it contains useful general info about the VN. And note that there's a low chance you'll get the true ending on your own (seriously, it's tricky to get) so if you want the true ending the first time you read Steins;Gate, use this flowchart!
Texts could be skipped easily by pressing the "Ctrl" button, however, when you reach a step where you need to decide whether to take out your phone to cancel D-mails or call someone in order to continue to different chapters and endings. the skip will stop.
In the game, if players decides to read the text only and just don't do anything all the way through Chapter 6, they will automatically proceed to the Suzuha ending.