My dogs eat a raw diet now, but when they were on kibble I did a lot of research on choosing food for them.
Here’s a set of “rules” I came up with:
1) When I chose a dog food, I chose one high meat content. I want to see preferably at least 2-3 out of the top 5 ingredients be meat or meat meal (first ingredient must be!). “Meal” has the water removed, so “chicken meal” actually has more meat thant he same weight of “chicken”.
2) I want to see higher quality grains, such as barley, brown rice, and oatmeal, instead of seeing wheat and corn. Or an alternative starch/carbohydrate such as potatoes or sweet potatoes. (Dogs actually have no nutritional need for carbs; but all kibble must have a carb/starch, otherwise it wouldn’t hold it’s shape and would be “crumble” instead of “kibble”.)
3) I don’t want to see any byproducts.
4) I don’t want to see a lot of fillers (beet pulp, brewers rice, etc).
5) I don’t want to see preservatives that are believed to be carcinogens (BHA, BHT, ethoxyquin).
6) I don’t want to see artificial colorings such as the Red, Blue, and Yellow dyes.
7) I don’t want to see added sugars (sugar, corn syrup).
8) I don’t want to see mystery meats (meats identified only as “meat” or “poultry”.)
Here is an article about byproducts: http://www.dogfoodproject.com/index.php?page=ingrd
And an article on what ingredients to avoid: http://www.dogfoodproject.com/index.php?page=badingredients
This website has a pretty good rating system: http://www.dogfoodanalysis.com/dog_food_reviews/
If you’re interested in raw feeding, here’s a good starting place: http://www.dogster.com/forums/Raw_Food_Diet/thread/431875