There are basically three steps to trim your toenails properly.  The first thing you need to do is get the proper instruments.  Most people have the typical nail nippers that push down between your fingers and it cuts the toenails.  These are okay for normal-looking, normal-thickness nails, but if you have a thicker nail with a nail fungus, you should get the heavy duty nail trimmers that are used kind of like scissors.  Be careful, especially if you have diabetes or any other conditions, or you have a lack of sensation or lack of blood flow.  When you are trimming the nails, try to trim them straight across. I do not recommend trimming into the edges if you are trimming them on your own. A lot of the reason I see people with ingrown toenails is because they are constantly having to trim out the edges. If you are trying to trim out the edges, or if you feel like you have to, it is usually because you have an ingrown toenail and you should see a podiatrist.  The third thing is if you are trimming your toenails and you find that it is painful on the edge, if you cannot get out the edge, if it looks red, infected, or swollen, you should probably see a podiatrist and get some help.  So, those are the three tips on how to trim your own toenails.  

If you want to learn more about how to treat ingrown toenails click HERE.