Now that your child may have mastered pointing to desired items they may be very persistent at requesting what they want or need! What I would do is a mental inventory of favorite items so that you know if he or she is pointing in the vicinity, you can then guess what they want correctly.
A great method to decrease frustration is to give choices. For example, during mealtime hold up milk and water or cereal and oatmeal and ask them to point to what they want. It will usually happen naturally. You may need physical prompting at times, even showing them how to isolate their index finger to point.
Always make sure to label items. “Do you want the strawberries or the yogurt?” while you bring each item forward to emphasize the name of each item. When they point reinforce the word again. “Oh you want the STRAWBERRIES yummmm!” The more you repeat the vocabulary and give choices the more likely they will store the image in their head and have a label for it and one day… they will say it! Other circumstances you can give choices in is play time, story time, bath time, etc.