It's very easy to be a frustrated Democrat these days; supposedly Obama and McCain are tied in the polls (although I am highly skeptical of that); there are still lots of people who are uncomfortable with Obama for various reasons; there will always be people who think he's a Muslim.
The best way not to be frustrated as a Democrat right now is to realize that the frustration comes from still being trapped in the Bush Administration. For all of Obama's great speeches, he's still not President. We're still a couple of months away from the election, and then a couple more months from his inaugural.
But he's doing very well. McCain's attack ads haven't worked the way Bush's did against Kerry. The Republican party is on the verge of a historic, once-in-a-generation collapse. One reason McCain is the Republican nominee is that many Republicans think that many people will vote for him because he is a "man of honor."
But that's all that McCain has going for him. In terms of policy, he's basically Bush all over again. His reputation and his status as a POW are the only things that are giving Republicans a shred of hope.
The big problem for Republicans is that there isn't another presidential candidate waiting in the wings who survived 5 1/2 years in a prison camp and can claim moral authority because of that. Which means that if and when McCain loses, Republicans will be judged on their policies. Which are failures.
So the best way to not be a frustrated Democrat is to start imagining what life will be like when not only is Bush out of office, but the Republican party starts to collapse.