Later, when Jon Pertwee took over, his new clothes were more realistically introduced by having The Doctor lift them from the changing room of the hospital where he is taken at the start of Spearhead From Space.
But it was Tom Baker’s transition scene that was the first to make some play on the anticipation of what The Doctor would be wearing.
Looking through the list of regenerations, I have realised there seems to be two dominant scenarios for these scenes:
The Hospital Changing Room scenario
The Third Doctor steals the clothes of a hospital consultant before stealing his car as well; after the Eighth Doctor emerges from the morgue, he takes the clothes of a surgeon, who is going to a fancy dress party; the latest regeneration sees the Eleventh Doctor lifting a the parts of his costume from the hospital locker room as he strides through.
The TARDIS Dressing-up Room scenario
Although we don’t see the dressing-up room, the Fourth Doctor keep popping out of the TARDIS dressed in unsuitable costumes; the Fifth Doctor finds his new clothes in the TARDIS, almost as if he was supposed to; the Sixth Doctor is the first to be seen in the dressing-up room to choose his new clothes; followed by the Seventh Doctor who goes through a similar selection; finally the Tenth Doctor makes his choice from a re-imagined dressing-up room, courtesy of The Mill’s special effects gurus!