Being late for an appointment can be very upsetting and often embarrassing, especially if you miss someone or are being charged for your tardiness. It's a matter of training and both your brain and body must be involved. If the appointment is early then do all the preparations for the meeting or whatever the night before. If you are meeting someone important then you can also shower before bed instead of leaving that to the morning.
In recent times I have had to leave home early and on one of those occasions needed to be at the airport at 5.15 a.m. to catch a flight. Everything was packed and ready the night before right down to the clothes I was to wear being laid out on the spare bed. I aimed to rise by 4 a.m. as the airport is some 30 minutes' drive away and I wanted to eat breakfast before leaving. That meant the latest I could leave home would be around 4.40 a.m.
My training in this regard is self-administered discipline and anyone can accomplish the same by being focused and forcing oneself to follow the orders as if you are directing someone else. You are your own boss, so be one.
There is no way that my arrival is late and to the contrary it is usually always spot on time or close to it, erring on the side of early. That means that anyone can use the same techniques to overcome the bad habit of being late for appointments, or worse - not turning up.
Get the paper-work in order as well, if this is appropriate. If you have to take certificates or other things to a special meeting then get them ready the day before and put them into a nice plastic cover or folder so that you look intelligent and on top of things. Impressions are everything and the best you can be when you arrive at a meeting the more you will enjoy it and overcome any nerves.
My experience with meetings is rather extensive as I am often sent to meet with people on matters of importance. My spirituality took me away from business and it allows many to be healed instantly by the Spirit, with whom I am linked. With memory of my reincarnation and with much to tell others I do public speaking and other things that require punctuality and good presentation.