Too often I see someone fail a roll, and simply make another one in the same post. Fortunately, there is a system in place for this...
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Trying It Again (VtM, page 193)

Failure often produces stress, which often leads to further failure. If a character fails an action, he may usually try it again (after all, failing to pick a lock does not mean the character may never try to pick the lock again). In such cases, though, the Storyteller has the option to increase the difficulty number of the second attempt by one. If the attempt is failed yet again, the difficulty of a third attempt goes up by two, and so on. Eventually, the difficulty will be so high that the character has no chance of succeeding (the lock is simply beyond her ability to pick).

Examples of when to use this rule are: climbing a wall, hacking into a computer system, or interrogating a prisoner. After all, if you couldn't find a handhold, defeat the security program, or get the prisoner to talk the first time, there's a reasonable chance you might not be able to do it at all. Sometimes the Storyteller shouldn't invoke this rule. For example, failing to shoot somebody with a gun, detect an ambush, or keep on another driver's tail are to be expected in stressful situations. Such failure does not automatically lead to frustration and failed future attempts.
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