Crafting some items will require a certain mastery level. This is shown by a special indicator on the recipe. The mastery level is not general, but specific for each category. It's depicted as an icon with a number.
The higher the mastery level, the more recipes are available to you.
To increase your mastery level in a certain category, create accessible recipes and get experience. Sometimes the level increases immediately, in that case instead of the experience bar there will be an Upgrade button.