The Feywild is considered a “mirror plane,” of the Material Plane (as is Shadowfell). If something exists in the Material Plane, then it exists in the Feywild as well but in a different form.
For example: The Unbroken Mountains in the Material Plane are mirrored in the Feywild as the Glass Pyramids of the Ever Dreaming
Even though the Feywild is an echo of the Material Plane, doesn’t mean it can be mapped or made sense of. Physics and logic are loose here and emotion runs wild. If you’re a ten day trek from the Unbroken Mountains in the Material Plane you may only be an hour from the Glass Pyramids. Or 5 years. It depends on your own emotion as well as the emotion of the Feywild itself.
Time
Time does not move in a linear fashion in the Feywild. Going into the Feywild and coming back to the Material Plane may take ten minutes, 10 years, or you may travel back to an early date than when you entered. Powerful Archfey have a small control over this.
While in the Feywild, the emotional wellbeing of the Feywild and yourself affect how time moves. If you are in a good mood and happy, maybe time speeds up in your travels as you enjoy the journey. Or maybe it slows to a crawl as you are so enthralled with everything you are taking in. Take care in the Feywild as some have found themselves lost for centuries despite only minutes passing by to them.
The Sun
The Sun does not rise and set based on any time table. Rather than cardinal directions like North, South, East, and West, most Fey use the sun and travel Dawnwards, Duskwards, High Noon, or Nightfall.
Example: “To see see the Winter Court, travel Nightfall until gloom sets in and you no longer believe in yourself.”
Nothing is as it Seems
The Feywild is full of deceit and whimsy. A small path of flowers may actually be trolls sleeping in the ground. Two birds dancing and flying in the air may actually just be an Archfey singing a song. One’s reflection in the water may be a Fey trying to steal their looks.
Observe everything, trust nothing.
While in this plane, magic may work differently and may contain its own rules. One of these is rules is the Rule of Threes. In the Feywild, the Rule of Threes is ever present. Starting with the original rulers, Queen Mab, Queen Titania, and the Moonlit King, it trickles all the way down into everyday life there.
Something we would take as coincidence in the Material Plane such as running into the same person three times on a long journey is more of a magically bound ideology in the Feywild.