Crying doesn't mean you are weak. You usually feel like crying when something important to your eyes is happening.
If you wouldn't care, you wouldn't cry.
On the moment, you may try at first to acknowledge and analyse the reason of the emotion.
Then, concentrating on your breathing may help on the moment. But I don't have all the keys to avoid it!
Maybe the times when you feel like crying more would be times when you have more stress (changes in your life, affective disappointment, work pressure, etc.). Sometimes it is good to acknowledge that you need to sit back and relax, we are not robots 