Consistency in control of the technique is one of the points where young athletes have to progress . Everybody can have a good throw , but everybody can have also a bad throw. the difference between a beginner and a champion is that the champion , being more confident in his technique , will be able to focus more on the fighting spirit needed by the competition.  The best way to build a reliable technique is to work first on having good postures during the key phases of the throw , this will provide control and balance and allow progressively to build and use more speed . Remember that it is not because your athlete has done a good throw in training that he will automatically reproduce it in competition . In fact it’s mostly just the opposite and it is certainly very frustrating . Who has never heard ”Ah yes , but in training , I have done this or that etc…” . To copy a famous saying : ”The real individual technique is what is left when the athlete has forgotten all what his coach has told him !” . In our exemple , young multi talented Fernanda TIRADO did not do too bad in 2 of her competition throws for a PB , but she did also quite a few ”not too good things” in some other throws . There is still work to do , but she is certainly on the good road with rather surprisingly good postures and technique for her age.  Available documents : 1-PDF technical analysis ; the good and the bad.   On the making : 2-Video analysis.