When clearing space you need to remember to clear the perimeter of your home. Many people ignore the outside areas of their home when doing house blessings or clearings. The land around your home is also important to bless and clear because it sets a spiritual boundary that is in tune with the physical one.
My favorite tools are salt, sage, and good intentions. You can do the energy clearing yourself but I recommend this only if you feel confident you can stand strong against any negative energy you may encounter in your home. If you have a severe energy issue or a haunting causing noticeable distress, I would advise using a spiritual professional in any discipline who has experience with previous blessings, ghosts, and other extreme energy clearing situations. If you are very fearful, it is also a good idea to have someone else do the blessing. I do believe the owner of the home or primary resident should be present during the clearing because their emotional link to the property adds energy to set the energetic boundary in the ethers. If you do not have access to sage, cedar or frankincense incense is a great second choice. If you have little kids, pets, or are generally concerned about fire risk, you can use a sage spray also. These are not quite as effective but, good enough if you focus your intention and use a little salt as well. Salt can be used around the entire perimeter of the property, all doorway thresholds, window panes, corners of each room, and any additional area you feel it needs to be there. Try to leave the salt at least a few hours after the clearing before cleaning.
If you use candles, use one black and one white, or you can use one of each on each room. Start the black candle a while BEFORE the white one. Get the black candle burning out the negative energy before bringing in the light, creating space. There are various theories about windows open or closed during energy clearing work. My personal feeling is windows closed is best. Energy work is not an exact science and other energy can enter while you are clearing out. There are many who would disagree with this, but in my experience, especially after clearing highly haunted homes more than once, is that closed windows gives you a chance to really work in a focused way on clearing out the energy in the home without interference. If the sage becomes intolerable, however, of course open the windows. Or you can take a small break and then continue. Please be practical at all times.
I recommend starting your energy clearing when you have a generous amount of time. You do not want to be rushed when doing something this important. There may be things that take more time and energy than you anticipate in the process of the clearing. There are many times you may want to clear a certain area more than once during the same blessing as well.
If you want to time the clearing with the waning moon that is a nice idea to assist in removing negative energy and preparing for new beginnings.