We all are once beginners, and there is nothing shameful aboutthis. In the end, no one is born with any knowledge or skills. Andany activity, whether drawing, learning foreign languages
orfitness, each person comes in due time (and sometimes, thatdoes not come at all). The main thing is not to think that it's toolate to begin at twenty (thirty, fifty ...), and also not to be lazyto search for information necessary for beginners and do nothesitate to ask questions to knowledgeable people.
And it is especially important in fitness and sports. Insufficientlyresponsive to their first steps, you can not only not achieve anyresults and discourage the desire to continue, but also harm yourhealth. Therefore it is very useful to know which mistakes aremost often made by other newcomers in order to avoid them.
Select an excessive training mode. 
Even basictraining programs, which can be obtained from a coach in thegym or found on the Internet, are still designed for a person witha certain physical training. If you are a complete beginner in thismatter, you should not even try to conscientiously implement theprogram. In the end, you just get out of your way and at bestthrow out workouts, and at worst you will get injured orundermine your health. Focus on your own feelings and do not beafraid to reduce the load, feeling that the current you can notafford. Even if you are dealing with a coach or in a group, do notbe ashamed to look the worst, because this is not a competition. The main thing is to work on yourself and gradually improve yourresults.
Consider the first step to purchase the mostadvanced equipment and equipment. 
Of course, it is difficult topractice yoga without a sports mat, and it's dangerous to startrunning without good sneakers. But do not postpone traininguntil you can get the best props. Start with what is, or buysomething inexpensive and relatively high quality. After all, there is no guarantee that you do not change your mind aboutthis particular sport or fitness and do not decide to try somethingelse. In addition, it may be that inexpensive equipment will suityou for quality.
Immediately begin training, without studying atleast the basics of fitness and features of the chosen direction. 
This is a direct way to low efficiency training and dangerousinjuries. Going to the gym, you need to know that after strengthtraining you need to recover within one or two days, otherwiseovertrain. You also need to carefully study the correct techniqueof performing any exercises, even if at first glance they seemvery simple to you. For example, a set of exercises for practicingpilates can be found in a few clicks of the mouse - and this, andso, and for beginners, and for advanced ... But it is unlikely thatit will be accompanied by a description of the correct breathingtechnique, absolutely mandatory for this type of fitness. It isunderstood that if you have started to search for a set ofexercises, you are already familiar with the basics.
To think only of efficiency, forgetting aboutpleasure. 
No training will not be useful if you go to it, like hardlabor. You will not feel the miraculous effects of yoga onyourself, if you struggle with sleep in class. You willsubconsciously rejoice at any "objective" reasons not to go to thegym if you can not tolerate strength exercises. Do not choosetraining on the principle of "where I burn an hour in themaximum number of calories" or "where I quickly pumped up theass and press." Better find something that you really like. Suchtraining you definitely will not abandon and will engage in fulldedication. The result will not be long in coming.