Now how this works is, during practice you always have choices of 6 practice programmes to take part in, these range from tyre management to qualifying runs and race pace.. Obviously if you end up doing all 6 in every practice weekend, you get this done a lot quicker!
You earn whats called Resource points, which you can put into upgrading your car.. The more you have, the more you can upgrade!
Once in the motorhome, before you click to go to next practice etc, scroll over to Research and Development, and click on View RnD tree.
But of course, upgrades do take time, so for instance quality control and factory efficiency are instant upgrades but are very expensive.. where as things like fuel injectors and upgraded engines etc they will take time, and sometimes up to 2 or 3 races to arrive, and you cannot move onto the next upgrade until the current one is being done. Thats why this could take you to the end of the season, maybe a bit before, but as for me it was China in Season 2.
I also just focused on the powertrain section as the Durability and Chassis department has new rule changes for season 2 , and if you hadn't upgraded them full by season 2, you would have lost everything and need to start again!