building is not very important in first couple of seasons. increasing the prices to the max level will do the job. one thing that should not be done is to enter transfer market immediately. a good assesment of current squad and buying youngsters with potential at low prices is a good way. while mvp or hall of famers above 25 are not useful for training, newcomers tend to buy them over the normal prices.
i won't say that, start building early and try to avoid max prices, you wasting money with it - try to get your prices around 66-75% of the price range maybe you wouldn't start so fast but i believe in the long run you will be ahead.
But good trainees are also important at the begining, i am not that much into the transfermarket, but maybe even less potential makes it, because you mostly won't use the potential - so a solid potential like star is enough.
Good training and arena, is your best midterm and longterm startegy.