There are tons of websites that will tell you exactly how to get a shine on black leather boots. Some of them even suggest ways to get different levels of shine. One thing that isn’t covered by most of those instructional pages is what to do when it goes wrong, or what to do when you no longer want glossy boots (converting an old pair from uniform/dress wear to a more outdoor role).
The most common problem I have noticed in polishing boots is people who are new to boot-blacking will often use too much wax or apply wax too quickly, not giving it nearly enough time to bond between coats. This often results in the wax cracking and flaking off. For this particular problem I recommend wearing the boots for a while to help the excess fall off before moving on the the normal removal process, to make removal easier.
The technique I use to remove polish from boots I learned from my friend David, an airman. The secret to removing polish from boots is to use metal polish. Specifically Nevr-Dull wading polish. All that is required is to rub the wading over the surface of the boot, let it sit for 4-8 hours, then rub the boots with a soft, damp cloth. Because the wading is designed for use on metal, not natural leather, there is some risk of the leather becoming dry and brittle after using the wading to remove the polish. To minimize this risk, apply a good coating of leather conditioner (conditioners made specifically for boots work best) after the polish has been removed.
Before attempting to add a new layer of polish the boots should be fully dry and all excess conditioning agents should be removed from the leather to prevent blemishes in the new layer of polish.