Successful drilling depends not only on using the right drill bit for the job, but also in using the right techniques to guarantee accuracy. As well as choosing the most suitable drill bit, pay attention to which tool you are going to use for the job in hand. Depending on the material & size of the bit, it could well be that a small archimedean drill will allow you more control than mounting the bit into an oversize power drill. A little thought will also save you breaking more drills than necessary.