How can I make my singing voice less nasal without taking singing lessons?

You must sing from your diaphragm if you want your voice to sound less nasal. You should sign up for the school choir since they teach you how to do this. Choir teachers are great. If signing up for choir counts as singing lessons look up on the internet how to sing form your diaphragm or look for it on YouTube. You should put your hand over your stomach and if you are feeling movement you are singing from your diaphragm, if not keep on trying, it took me awhile to learn. Hope this helps you.