The best order to watch Steins Gate is in chronological order to get a comprehensive understading of the anime series. Let's look together the right sequence:
Watch Steins;Gate Episodes 1-22 set up the story and characters background. At this stage, Steins;Gate story is quite straighforward.
Watch Steins;Gate Open The Missing Link is an alternative ending episodes which sets things up for Steins;Gate 0. In fact, Steins;Gate 0 is a mid-quel of the original anime series.
Watch Steins;Gate 0 is the mid-quel of the original series as is placed inside the original story of Steins;Gate. The series is located before 23-24 episode of the original Steins;Gatrre series.
Watch Episode 23-24 of Steins;Gate. Episodes 23-24 of Steins;Gate wrap around the entire story of the anime series. The near-perfect ending for Okabe and Kurisu.
Watch Steins;Gate: The Movie - Load Region Of Deja Vu. The movie of Steins;Gate takes place after the ending of the series. The storyplot of the movie is superfluous for the anime series and should be regarded as OVA.