How can I clean the yellow brown spots from my teeth? (photo)

Your first step should be to get a cleaning by a dental hygienist.  It is likely that this will not remove the stain, but it will remove any plaque/bacteria that is contributing to the staining.  The second step should be to get an x-ray of the tooth along with an exam by a dentist to inspect for cavities.  The third step would be to have a veneer placed for a permanent fix, or just have bonding done as a temporary fix.  Either way, removing your stains is a very, very easy job for a cosmetic dentist like myself.  I have done this thousands of times.  I'll include a link of before and after photos; the photos at the bottom show the removal of stains with bonding.  Other photos show removal of stains using veneers or crowns.  Good luck and I hope this helps. Follow me if you have more questions.Sarah Thompson, DMD

Your photo is not clear so it's my request to upload a clear photo. But By seeing your photo, I feel its intrinsic stains on teeth. In such conditions, porcelain veneer is the best option.

It appears that you need a good teeth cleaning followed up by regular cleanings.  This is a very easy problem to solve.

Cleaning helps removing the layer of tartar(calculus) and stains. After full mouth cleaning, your cosmetic dentist can suggest you teeth whitening, porcelain veneers or composite bonding for more correction.
Ideally, Teeth cleaning should be done in every six months. The layer of tartar has millions of bacteria and it creates space for bacterias to harbour on the teeth and gums. Gums lose grip on teeth because of these bacterias and not cleaning. Ideally, you should never let layer of tartar to form. Brushing twice a day and professional cleaning in every 6 months saves you from gum problems and cavities. 
Cosmetic dentistry can help you achieve the smile of your dreams, you really need to shrug your worries and get your smile rejuvenated. 

Hello and thank you for your question. The good news you have options. And to reasure you dental cleanings do NOT "make gums to lose their grip" on teeth. Hopefully stains will come off with a cleaning, posibly a deep cleaning. In case it will not, you might to consider dental bonding or porcelain veneers. You will have a great smile if that's what you want!