I believe that any type or form of a blessing should be performed with utmost love, devotion, and positive energy to the tool made before any other pointer or tip comes up as a potential idea: those first few energies is what does the true blessing. Next, I again believe that a blessing should be done in a way that is most suitable to the person doing the blessing. For me personally, I usually whip up a positive energy filled chant, vision white mist going into the object with will through visualization, and use water and salt from my ex Lutheran roots. I mainly focus on how the good energies bring about blessings, but that is just me! In any way a blessing pertains to you, go by intuition and stick to it! If you have any questions, please feel free to ask! ~Sullenmoon
Depending on what diety you worship, you could ask them to bless it, or you could expose it to the element(s) that represent them. Also passing it through incense smoke that has blessing, purifying or just positive energies works wonders.