If you have a lower potential player (probably up to 8 potential) it does not matter much. Otherwise for high potential players the end skillset often depends on how fast you can add skills which means you should train the fastest training skill you plan to train (which in the near totality of cases will be 1v1).
When you have trained enough of HA/DR (for the end skillset you want to achieve even considering the secondary training HA/DR will receive from other training regimes) or if another skill becomes faster than 1v1 due to negative elastics, then you should train the fastest skill which still fits in your plan.
You can check the estimate of the training speed for your players with coach parrot, it should be fairly accurate.
As Westri suggested it also depends on your individual situation and what you are doing with the other trainees (example: I have a 26yo forward that only needs OD and I'm training him alongside youngsters, so I'm training OD first this season and I will move to 1v1 next season when the older guy won't need anymore training)
Last edited by Lemonshine at 02/15/2017 13:02:57