Here are some foods that are rich in calcium that I include in my diet on a regular basis:   

1. Canned Salmon: When it has bones included, this easy to prepare food is full of calcium! I use it to make salmon loaf with rolled gluten free oats and veggies, or stick some in a gluten free tortilla for a quick and tasty lunch.   

2. Leafy greens: While a fiber restriction prevents me from munching these whole, I regularly include them in smoothies or make fresh fruit and veggie juice with oranges (also a source of calcium :)), carrots, and mixed greens. 

  3. Firm tofu: This is something that I can enjoy in small amounts, so I will use olive oil and cornstarch make "crispy tofu" and veggies in my cast iron pan for lunch about once a week.

Katie Hansen, M.S.W., is a veterinary technician and lives in Seattle with her husband, Jim, and their two dogs.

One of the first things a doctor usually tells you when you are at risk for bone loss is to make sure you are getting enough calcium.  Calcium is important to building and maintaining bones, but simply increasing the calcium in your diet often is not enough to build stronger bones.
Most sources I've read agree that several other elements are needed to absorb and use calcium:

Vitamin D3
Magnesium (citrate for better absorption)
Boron (in some multivitamins)
Vitamin K (a good source is alfalfa)

And doctors now are saying that at least half of the calcium we take should come from our food, rather than supplements.
One of my favorite calcium-rich breakfast foods is a smoothie made with kefir (it's like drinkable yogurt, high in calcium and high in probiotics and is supposed to be easily digested). You can add strawberries, peaches, blueberries, ground flaxseed, protein powder, and even spinach or other greens.  And you don't taste the spinach!  
To sum it up for today:  a good diet is a good start, but must be combined with weight bearing exercise to stimulate bone growth.

Not this....bone building exercise must be weight bearing. Swimming and bicycling have not been shown to build bone. Walking also is not effective for people who weigh less than 127 pounds unless they use a weighted vest or backpack. Photo by arztsamui, courtesy of  freedigitalphotos.net

Core exercises can help build bone in the hips and spine, along with strength training, jumping, and other movements that load the bones.
Photo by stockimages courtesy of freedigitalphotos.net