Creating a great performance requires a lot of preparations. Imagine your project works in school but multiply it by 1000 times. From liaising with the event coordinators to communicating with the stage crews, performing live is not only the art of musicianship but also intricate collaborations. It is quite obvious that Murphy's Law is most probably going to be your worst enemy so it is important for everyone to cooperate and fight against all odds.
Below are the lists of observation I have made through years of working in technical production. In my opinion, these suggestions do not require much effort to execute but it's one of the most practical and effective practices for anyone to adopt.
Know you gear and instrument well
This is similar to your school presentation, ultimately; you will be the one on stage performing so it is essential for you to know what does your gear do. Understanding your gears and instruments is not as difficult as it sounds. Simply put, you need to know how to work your gear, how to interface them together and most importantly, try your setup before going on-site to realise that this is not the sound you're looking for. It is not required for you to really understand what type of impedance loading work best with your instrument. Nonetheless, there are exceptionally good guitarists such as Jonathan Lee or Linda Taylor who are very particular with their setup and have spent years on studying guitars.
Whether are you treating this as a hobby or profession, you should also invest in some necessary items such as cables, drumsticks (if you're a drummer) or batteries. Your performance does not only encompasses you and your instrument, it comprises of everything else that is needed to link your instrument to the audio system. Preparing your own guitar cables and making sure that instrument are ready for the show (e.g. having a functional mouthpiece for your saxophone) are just some simple steps to reduce the possibility of your performance going wrong.
Update your rider
A technical rider is a document that gives the venue and/or the sound crew an understanding of what your technical requirement are and how to set up the stage before you arrive. A rider should include the band/stage layout, the instruments that needed to be mic/line input and the powers requirement for your set (e.g. power bar for your pedals).
To save time, you should have different versions of technical riders for different applications. There are bands that categorise their rider into venue spaces (e.g. tech rider for clubs, auditorium, road shows) or set versions (e.g. tech rider for full band or acoustic set). Choose the one that applies to you the most and update them when necessary. A rider is the communication medium between you and the sound crews before you arrived at the venue. It must be concise enough to indicate the necessary tasks for the production crew to prepare in order to prevent time wastage. If you are not going to play a particular instrument in the rider, have the courtesy to remove it.
Having a set list
This might be the simplest item in the list to prepare. A set list basically includes the songs (in ascending order) you and your band are going to play in. It can as cheap as writing it down the lists of songs on a piece of paper that is easily legible on stage in a dark environment. A set list helps to bring every of your band member to be on the same page, for instance, which songs to pause or not to pause after every interval. Believe me, I have seen so many unnecessarily mistakes by bands playing the wrong songs and having to restart all over again just because of a miscommunication. That is as embarrassing as it gets on a live stage.
Learn how to play to the room
Different room have different acoustical characteristics, thus you might have to adjust your playing style to accommodate the room. The bigger the room, the louder you should play. This is why it so important for bands to get a feel of the room and the balance of their sound during sound check. It's always a shame when an excruciating loud guitar amp destroyed a nice performing number. Your performance represents your band identity and it consists of all the band members, not just the instrument that overwhelmed the rest.
Treat the equipment with care and respect
Before you do anything else to the equipment than its intended use, do check with the engineer or owner whether are they cool with it (e.g. "drop the mic"). Unless you own or you are ready to pay for the equipment, treat the equipment with care and respect. After President Obama "Drops The Mic" viral video, there was an increase in cases where people would want to mimic this action to state they statement. In reality, many of them do not know the cost of a microphone (e.g. Shure SM58 would cost around $150 SGD) and refuses to pay after damaging it. I do not blame the president of United State for this trend (I sure that Mr. Obama will be able to pay it anyway) but do bear in mind that these equipment are not yours, thus you would have to take care of it.
Making a statement or having a cool pose on stage does not justify the abuse and inconsiderate actions to a good piece of equipment. Example, if you need something to step on while performing your solo, the stage monitor speaker (wedge) is definitely not the place to go. Prepare a box or ask around for something less valuable to step on. Not only does this ensure the equipment are performing at nominal conditions, to also prevents the equipment from failing during the performance.
At the end of the day, it is everyone's objective in the production team to put up a good show. An iconic live show requires a lot of preparation and not just entirely depend on miracle.