I find when I want to measure my resting heart rate, and important number in characterizing the heart, I count for one minute, yes I look at a watch or clock. That count is the heart beats per minute. For most adults that is between 60 and 80. I can be a bit lower and higher without it being a problem indicator.
As for irregular heart beats, that's it, if the time between pulses is noticeable and repetitious one has a heart arrhythmia. This too may be something that isn't a serious problem, but it should be checked. I suffer from a condition called atrial fibrillation and it causes my resting heart rate to be fast (80+ at rest) and irregular.