Tthe Fender Stratocasters modern, unique body shape (officially known as "Comfort Contour Body") was inovative for its time comparing to flat guitars such as Telecaster. It's double cutaways allowed access to higher and lower frets with the same ease. Body shape, which was designed with players comfort in mind, have distinctive curve on the upper back and small ergonomic curve where players arm rests.
Comparing to Telecaster, Stratocaster have wider headstock with the same non-angled design and 6 in-line tuners in order to lower the friction between the strings and the nut and easier manufacturing. This was designed having in mind tremolo to allow strings to stay in tune. To stop the strings coming out of the nut string retainers had to be used.
Stratocaster features pivot-bridge going trough the body which is attached to the guitar with 5 springs easily accesible by removing the cover on the back of the guitar. This way, after using tremolo, bridge is returning to original position since strings are pulling in one direction and springs to another making it neutral. Some playes, who dislike the instability of Stratocasters tremolo mechanism (such as Eric Clapton), and failure to stay in tune used to block the tremolo by sticking piece of the wood and block the gap towards the body of guitar.
Comparing to other guitars of that time Stratocaster had 3 single-coil pickups with the 3-way output selector which is later replaced by 5-way switch allowing combination of 2 pickups simultaneously as well as each of the pickups alone. Different type of Stratocasters today have different combinations of pickup selection for each switch position. The volume level is controlled by one volume knob for all three pickups. This knob is positioned in such way that it could be easily used while playing without moving the hand from the strings.