I am a big proponent of brining turkey before roasting it. It always turns out moist and juicy, never dry. See the recipe I use here.
Here are some things to remember when brining any meat:
Kosher salt and table salt (without iodine) are the most common salts used in brining. Sea salt can be used, but it tends to be quite expensive.
A cup of table salt and a cup of kosher salt are not equal. Table salt weighs approximately 10 ounces per cup and kosher salt weighs approximately 5 to 8 ounces per cup depending on the brand. If using kosher salt in a brine, you must use more than a cup to achieve the same "saltiness" you would get from a cup of table salt.
The chart below shows how to substitute the two most popular brands of kosher salt for ordinary table salt.
1 cup Table Salt (without iodine) - Substitute with:
Diamond Crystal Kosher Salt = 2 cups
Morton Kosher Salt = 1-1/2 cups
You can add flavor in all sorts of forms such as herbs and spices. Use brown sugar, honey or molasses in place of the sugar (some sweetness tends to offset a saltiness the brine might otherwise impart). You can use apple juice, cider, orange juice, rice wine vinegar, apple cider vinegar, stock, or other liquids to replace some or all of the water.
Read more about it here.