The following guide contains as few spoilers as possible, and is my recommended approach to playing the game. Any references to the "Flowchart" will be referring to the PDF flowchart document found here from the Steins;gate wiki.[steins-gate.fandom.com]

The flowchart contains minimal spoilers, and really only spoils chapter structure where relevant and certain conversation "flows".

Though not required, I highly recommend installing the Committee of Zero STEINS;GATE patch, which boasts improved translations, better text rendering, optional costumes and more.[sonome.dareno.me]

My recommendation is to experience the game twice over two playthroughs:

Go through the game and do things at your own pace, with one exception: do not respond to Kurisu's emails in chapter 4. Outside this chapter, you may respond to Kurisu's emails whenever you'd like.

Once you get up to chapter 6, I encourage explicitly making a save at some point after Mayuri makes a shocking revelation. The reason why will be made obvious as you continue playing.

If you get stuck in chapter 6 and are unsure how to continue, open the flowchart and read the first page, followed by the flowchart for chapter 6. It should become obvious how to proceed, and I highly encourage you to not read any further than chapter 6.

Otherwise, have fun! Once you experience the end of the game, it's time for a second playthrough.

Your goal now is to experience the true ending. Download the flowchart if you haven't already, and as you play through the game again, ensure you obtain all true ending flags. Keep an eye out for anything strange now that you've got context from the first playthrough, and consider taking some notes.

As you play, make sure to experience any alternate scenes you may have missed, such as the split in Chapter 2. Be sure to obtain the "Cruel Sister" and "Warrior Girl's Pride" achievements too, as they provide some extra content that doesn't require you to go out of your way to achieve.

I highly recommend experiencing all endings the game has to offer, and as such, keep the flowchart open as you play. If you missed out on any endings during your first playthrough, be sure to play through them now (with one exception), making saves where appropriate. That exception is an ending in "Paradox Meltdown" that occurs if you don't obtain all true ending flags; Since the true end already contains this ending, it's effectively a waste of time unless you're going for 100% achievements.

For those who'd prefer just a single playthrough, I've outlined my recommendations below. Be aware that this likely won't provide as rich of an experience, but will still serve you the essence of the story. I've also outlined some optional steps, in case you're VERY time restricted.

Before completing the following steps, download the flowchart I referenced, and refrain from reading portions beyond what the step specifies. Though it contains minimal spoilers, it's best to not even know what might be coming up during your experience.

1. Complete the Prologue and Chapter 1
   
2. Complete Chapter 2 with the flowchart open, making sure to follow the steps to obtain the Cruel Sister achievement and experiencing the Faris Cup scene
   
3. Complete Chapter 3
   
4. Complete Chapter 4 with the flowchart open, ensuring you obtain True Ending Flag 1 and the Warrior Girl's Pride achievement
   
5. Complete Chapter 5 with the flowchart open, and obtain True Ending Flag 2
   
6. Play through Chapter 6 with the flowchart open, and make a save before the end in the flowchart
   
7. (Optional, highly recommended!) Experience Chapter 6's alternate ending
   
8. Complete Chapter 6, making use of the save made in step 6 if necessary
   
9. Play through Chapter 7 with the flowchart open, and just like in step 6, make a save before the end in the flowchart. Ensure you obtain True Ending Flag 3.
   
10. (Optional) Experience Chapter 7's alternate ending
    
11. Complete Chapter 7, making use of the save made in step 9 if necessary
    
12. Complete Chapter 8 with the flowchart open, obtaining True End Flag 4 in the process. You can also experience the alternate ending here, though I feel it's not as strong as other endings.
    
13. Complete Chapter 9 with the flowchart open, and make sure to grab True Ending Flag 5.
    
14. Complete Chapter 10 with the flowchart open, ensuring you obtain True Ending Flag 6.