• Body design: Strat, Tele, Les Paul, PRS, Steinberger, etc.?  (There is a good overview in the inventory at Warmoth that you can jump to from here.)

• Wood: quilted or flamed face?  exotic woods?

• Finish: transparent (translucent) or solid or unfinished?

• Headstock: Strat, Tele, Les Paul, headless, etc.?

• Fretboard: maple, rosewood, ebony, etc.?

• Fret Markers/Inlay:
• dots (e.g., Fender Stratocaster, etc.)
• off-set dots (e.g., Godin, etc.)
• trapezoid (e.g., Gibson Les Paul Standard, etc.)
• block (e.g., Gibson Les Paul Custom, etc.)
• split block (e.g., D'Angelico, etc.)
• hump block (e.g., Gretsch Duo Jets, etc.)
• thumbnail (e.g., Gretsch some 6120s, etc.)
• birds (e.g., PRS, PSR-imitators, etc.)
• nothing (e.g., some custom Steinbergers, etc.)

• Color Scheme: chromo, gold, or black?

• Control Knobs: speed knobs, bells, plastic, metal, jeweled?

• Pickguard: black, white, mirrored, tortoise, mother-of-toilet-seat

• Single coils:
• standard pole pieces (i.e., traditional Strat-style)
• blank (e.g., Lace Sensor, EMG, etc.)
• Dynasonic (e.g., Gretsch, DeArmond, etc.)
• lipstick (e.g., Danelectro, Silvertone, etc.)
• covered (e.g., Telecaster, etc.)
• Hi-lo trons (e.g., Gretsch)
• blade/rail (e.g., some metal guitars, etc.)

• Humbuckers:
• standard pole pieces (e.g., open-face Gibsons, etc.)
• blank (e.g., Lace Sensor, EMG, etc.)
• lipstick (e.g., Danelectro, Silvertone, etc.)
• covered humbuckers (e.g., Gibson, etc.)
• zebra (e.g., EVH/Axis, Peavey Wolfgang, etc.)
• "invader"
• Filtertrons (e.g., Gretsch, etc.)
• Rickenbacker (e.g., 360, etc.)
• Tetrad (e.g., Godin, etc.)
• blade/rail (e.g., some metal guitars, etc.)

Even though this section is only about the aesthetic side of design, what your guitar is made of can play a role in other areas.  For example, I never used to believe it, but the wood in a guitar can really make a difference in the sound.  This is because the strings don't just vibrate above the pickups; they also resonate into the body.  This then feeds back into the strings and alters the way the strings vibrate.  And the cycle repeats itself iteratively to produce a characteristic sound of the guitar... regardless of which pickups are in it!

This phenomenon was brought home to me with my black Strat.  This was my first real electric guitar and was my exclusive instrument for many years before I started tinkering, so I really knew that guitar's sound.  It was a really clear, throaty tone almost like an oooh sound.  I loved that sound, but couldn't stand the 60 Hz hum from the stock pickups.  I figured I would just lose that sound along with the pickups.

I originally had a set of Lace Sensors in my red Strat, so I figured I knew their sound as well.  However, when I moved the pickups to the black Strat, I found that I had a combination of the two.  The guitar's body contributed to this sound to again deliver the characteristic sound I had always enjoys, only without the hum from the crap pickups.

Moral: In spite of the implied bias of this site to the contrary, guitar electronics are only one part of the sound.