I have puffy gums, frequent bad breath, and there is some yellowing in between some of my teeth. but i have pretty good hygiene. how can i fix this?

See your hygienist: When was your last dental visit? This might be as simple as having a hygiene appointment with your dentist or hygienist and enhanced hygiene. If your dentist feels that scaling and root planing is indicated, that should be scheduled as well. It might also help to have professional bleaching done by your dentist in addition.

Dental Care: Brushing and flossing alone cannot replace professional dental care. You'll need to be seen by a dentist and/or hygienist to have those teeth cleaned professionally. No matter how good you are at cleaning your mouth, you'll never be as good as your dentist or hygienist. Sounds like you have calculus built up, and that would cause your symptoms.

Not so: Your description indicates that there are some deficiencies in your oral health regimen. Regular professional care needs to be coupled with exemplary (not just good) hygiene to prevent pathology. Start with your Dentist. Referral to a Periodonhtist and/or an Ear/Nose/Throat Specialist or an Internist may be in order. You can't do this as purely DIY project. Seek professional help.

Simple solution: Puffy gums and bad breath can be a sign that you are at risk for, or already have a gum disease. See a dentist for gum disease evaluation, x-rays and treatment options.