First, OTK spankings are amazing for a variety of reasons. First, start with spanking through the clothes, and then remove them (or even hotter, tell them to remove them one layer at a time and resume the position). This warms them up and extends things in a very exciting way. Hands, hairbrushes, and other short implements are nice for these, but nothing with reach. You can't really get the extension you need this way.
Face down on the bed is good for using longer implements. Belts, canes, or anything with reach. Fold a blanket into thirds and cover the area just above the buttocks - this will protect some of the places you absolutely don't want to hit. Practice your strikes and see how much control you can develop. Play with the marks and space them out, or overlap them like shingles. This will help you to learn how to control the implements and avoid making any serious mistakes.
If noise is a concern (screams), you can have them scream into a pillow and turn their head to thank you for each strike or count them out. Keeping something like Neosporin, alcohol pads, ice packs, gauze, water, and snacks nearby will let you transition into aftercare without leaving them alone.
Happy spankings!