There is no requirement for singers to attend professional voice tuition classes, but these days there are wonderful vocal technique resources freely available online, that singers can use to guide them towards singing better. If you already love singing, it follows logically that you will love singing better even more!
Here are some links to good quality "how to sing" resources you might find useful:
Youtube playlist of Alexander Massey's "How to Sing" series: http://www.youtube.complaylist?list=PL35CB4D5C3385C594&feature=plcp
and his "How to Breathe" series:
Singing teacher (and Virtual Choir member) Henny De Snoo-van Breugel has created a Vocal Technique Tips site with lots of information and tips to help you improve your singing. https://sites.google.com/site/vocaltechniquetips/
David Burchell (choir director/conductor) is always telling us to smile when we sing - very good advice. This is what Henny says about singing with an open throat:
"Opening your throat is not just about relaxation. There is more you need to do to give your vocal folds as much room as possible.One of the best ways to give your vocal folds room is SMILE!
When you open your throat like this, you open your false vocal folds. By doing that you allow you vocal folds (the ones you sing with) to move more freely. Your breathing becomes more effective too."
The Vocal Technique Tips website has been set up specifically for the Virtual Choir 3 project, but it is an awesome resource for any singer, and it continually has more useful content added.
Here's another interesting tip from the same website:
"There are some do's and dont's when you are suffering from hoarseness or a breathy voice:
1. Drink a lot of water!
2. Give your voice some rest
3. Do NOT use any stuff that has menthol in it! This candy may taste good and gives you the feeling that is helps your throat but it will increase the swelling of your vocal cords and the tissue around it! Because menthol dries out the tissues in your throat, these tissues will react by producing more swelling and mucus. Your voice will only deteriorate!"