First of all lets understand what Mercury Retrograde actually is.
Mercury Retrograde is actually an optical illusion. It happens when Mercury is passing by Earths orbit but since its closer to the Sun than the Earth, from our view it looks like it's going backwards. When it is actually going faster than Earth. As it flies by us it is also lifting lots of debris and dust, and this is what brings up the clouds of confusion during a Mercury Rx.
First of all, all of the planets are not only external bodies in our solar system, they are present in our internal psyche as well. This is why they are all depicted as Gods/Dieties/Archetypes in mythology. Our ancestors somehow made the connection between the Cosmic bodies and our Selves in the most beautiful ways, which always proved to work because they were able to diagnose and treat many illnesses as well as prepare for many tragedies and take advantage of many alignments. The Cosmic bodies are responsible for our existence, have guided us since the beginning, and continue doing so.
Back to Mercury, when he goes Retrograde as we've established to the stargazer from Earth it looks as though he is moving backwards. So his backward illusion is the energy we receive and register here on Earth. This means everything that the planet Mercury rules or is known for gets delayed, re-routed, and sort of spins out of control.
To understand what may be effected during Mercury Retrograde we have to ask ourselves.
What does Mercury rule?
Communication, transportation and transmission of all sorts. Mercury also rules metal, so electronic devices of all sorts, and especially those that transmit energy or communication. Mercury rules the mind, learning, listening, processing, sharing, analyzing, planning, will all be inevitably influenced by Mercury's transit.
Mercury is represented by the Greek Messenger God, Hermes, you may understand much more about the psychological and physical effects of this planet by learning about this Archetype.
All of the things listed above are prone to weird malfunctions, delays, confusion, and so on.
Our mind may be on overload, hence the confusion. We may not have the patience and ability to focus on studies or registering too much information. Our speech and communication may be slower than usual, we may find it harder to find the right words.
In the day to day life, travel will be effected more than usual. Accident are more likely to happening as people are prone to speeding while mentally less coordinated. Travel delays whether its public transportation or flights, due to unusual traffic or random technical difficulty.
This is why Mercury Rx signifies a time for slowing down and re-visiting old projects, rather than starting new things. Work on the things you've already been working on, re-vise them, improve them, fix whatever needs to be fixed.
Mercury Retrograde is also notorious for causing miscommunication within relationships of all kinds, but since we are usually with our significant other, that's the one that can get hit the most. It's advised to avoid conflicts and arguments because they can escalate, due simply to miscommunication.
Mercury Rx DONT'S:
Plan and or take big trips that you don't have to. If it can wait until after the shadow period, then you're better off waiting. Chances are it won't be a smooth trip.
Start or launch new business ventures. Our judgement is off during Mercury Rx and so is communication, if you do start something just keep in mind you will most likely have to revise it or change it after Mercury is out of shadow period.
Sign contracts of any kind. Again, communication and judgment is off, all contracts are subject to change, this includes verbal agreements.
Make any major decision with business or career. It will most likely change and not go how you envisioned, causing you to re-vise it again after Mercury goes direct.
Mercury Rx DO'S:
Slow TF down! Theres a reason things get so whacky, often times leaving us no choice but to slow down during a retrograde. We are on constant autopilot motion, always rushing to get ahead. But unless we take the time do breathe, rest, reflect, we're not using our full potential. So anything else we do is pretty much half assed. if we take our time with everything we put our Soul and Heart into it, making it that much more meaningful and effective.
Reflect, revisit, revise, re-organize...this is really what Mercury Rx wants us to do.
Research is another important thing, while you are forced to slow down might as well sit back and research on whatever it is you're trying to achieve. This will have you ready for action when Mercury goes direct and out of the retrograde period, and everything naturally starts flowing.
This is all subjective and there will definitely be trips taken and contracts made during Mercury Rx, but just be aware that the inevitable consequences may follow.