I don't let myself feel it. If I hear myself thinking "I'm so frustrated," I immediately put the brakes on it and restate the feeling. I'll let myself be annoyed, tired, momentarily thwarted, lacking momentum, or not sure what to do next, but I won't let myself be frustrated.
Here's why. The definition is "a feeling of dissatisfaction, often accompanied by anxiety or depression, resulting from unfulfilled needs or unresolved problems."
Dissatisfaction in itself is not so bad. That feeling prompts us to change and improve our situation. But anxiety and depression are two emotions that can suck away our will and ability to do something.
If I believe I have an unfulfilled need or unresolved problem, feeling frustrated about it means I believe I am helpless to fix it. It is a form of giving up, perhaps because someone else should do something about it.
Well, I am the only person I can make do anything. So if a need isn't met, or a problem isn't solved, that's my own fault. I can't feel frustration because I have the power to address the issue.
Even if I realize that I may have no control over a problem, I still have the ability to be pragmatic and not waste brain power worrying about it. That dissolves any frustration I might think I feel.