What can I do to widen my smile (without veneers) so that my back teeth will show when I smile? (photo)

i can see large buccal corridors [dark portions] , so best option for you is damon braces [for maximum arch widening]. but if u r not interested in braces thn  invisalign is another good option. in india invisalign-FULL costing is US$3500. 

You are a great candidate for porcelain no preparation veneers in the posterior area. No shaving, looks amazing, widens your smile and blends in very nicely.  Make sure you go to an expert cosmetic dentist who makes them blend in beautifully with the remaining teeth,

Joseph Goodman DDS, DMD,  Beverly Hills  

Your best results would be veneers. Bonding is a possibility, but won't give you as good a solution. Invisalign probably won't be able to broaden your smile. Braces may work, consult with an orthodontist.

Hi:You should consult with an orthodontist to explore your options if you do not want veneers.  Invisalign and or braces can be an option.Best,Dr. Maddahi

I would recommend a consultation with an orthodontist for braces/Invisalign to widen your arch and improve the symmetry and harmony for your smile.