Start and finish soft
In any training always start at a very smooth pace, and go increasing the intensity throughout it.
To finish the workout, try to do a few minutes of gentle exercise at the end of the sport you are doing.
Do not forget about warm-up and stretching
It is very important that you spend some time in each workout to warm up and stretch, so you can prevent injuries and also by doing stretching exercises, you can run, and swim better.
Technique, a fundamental part of training
Dedicate part of the training to practicing running technique, swimming, cycling, although it may not seem like practicing this type of exercise, you will improve your efficiency in each sport and thus you will be able to obtain better results and with the same effort run and swim faster, avoid injuries , etc.
Pay attention to your body
Sometimes the training, work, and social circumstances that surround you influence your performance, and may make you feel tired, unmotivated, etc.
In these cases, it is important to listen to your body, and if it asks for rest, give it to it. Nothing happens to miss a day of training, it is even beneficial in some cases.
Do not try to recover the lost training
If you have never been able to do a training session, do not try to recover it by doing double the next day, let it pass, do the planned training and do not think about it anymore, that you are not going to lose your fitness.