Using specific skills at the right time and right sequence is another strong factor for you to win, especially for magicians and classes that needs to control their MP very well inside the olympiad, such as Duelists and Grand Khavataris. Watch an example in the video bellow:
If me or him had used the Battle Roar augment a little bit later, one of us could have lost the fight there, also if I didn't use the Batte Roar skill from the Duelist in the end at that timing, I would have lost, and that's why the skills order are so important, not only on Duelists, but for all classes.
For example in the video above with the Ghost Hunter class, I started using Bluff before of using all my damage skills, because for the case the Bluff works, as it did in the video, I would have them charged to hit the opponent on his back and give him more damage. If I had used the damage skills first and Bluff later, the damage skills would be on reuse delay and I would lose the Bluff time, making useless the Bluff time.
Also you can think about the skill's attack range to use your skills sequences, for example in the video I start with my medium attack range skills and instead if getting close to him to use Triple and Double Sonic Slash, I let her come close to me and then I use the short attack range skills. These kinds of situation are a little hard to understand at first, it becomes easier with practise, so don't focus too much on it from the start.
This topic was made for you to understand about it's importance from the beginning and start to use it as soon as you can creating your own skills sequences, because since there are 31 classes, it's too much to show skills sequences for all of them in just one topic, but there will be more about it in the mastery guides.