Going by your words orthodontic treatment is the best way to close space between your teeth. As u say , already ur teeth is  big ,crown or veneer might increase tooth size.

Hello, Gap closure can be done with cosmetic options like veneers/laminates or with orthodontic treatment.

Many options are available to fill these gaps. Braces treatment is ideal though it does take a year or so for treatment. You can opt for tooth coloured braces also. Besides these cosmetic options ( depending on how wide your gap is) are also available ranging from simple ceramic fillings to laminates and veneers. However these will need to be replaced after a few years.