The other posters have sound advice. If you are looking to become more comfortable with casting healing spells I am a big advocate for developing your own understanding of healing and creating your own spells. I feel they are generally more effective and have better results.
I would start by researching what area you are working in, so if you like using herbs in your spells, try researching the different herbal properties of some plants for incense or to even physically use (if that interests you). You can also learn more about some of the different gods or goddesses and custom a spell to honor one of them. Research is key and educating yourself. The spells do not have to be complex, and some don't even use spell casting for requests, its all personal preference.
Hope this helps!