You can’t protect yourself from ????? ????? ?? ?? ?????. It is actually important to realize that we are not in our own hands. There are Segulos Leshmira and there are protective measures, but don’t let this lead you to the understanding that it is you who is in control. This is the lesson we are to take from death, as the Pasuk states.
Having said that, a great Segula for Shemira is Betachon and the motto of ?? ?? ????? ????? ??? ????, in the real sense. When Rebbi Akiva and his Rebbi, Nachum ish GamZu, said this they meant that actual good thing will come from what seems bad now. They didn’t mean that it is good for them. This is illustrated in the story with Nachum ish GamZu’s sand and Rebbi Akiva’s candle, chicken and donkey.
You can also look at the Chida’s Avodas Hakodesh for some Tefillos.
But don’t make the mistake of the Dor Haflaga, to think it is in your hands physically (as in making a pillar to hold up the sky) or spiritually (as in going up to fight).