1. Memorize the Words - There are some very famous faux pas that have centred around not singing the correct words. One memorable hockey game had a fine singer who obviously had learned the words of Oh Canada from an old book because the words were changed slightly in 1967 when it became our OFFICIAL national anthem. In this case, Mr. Bean type schwa sounds will not do.
2. Practice - Do not assume that you all ready know it well enough to sing. Practice perhaps even more than for any other song. It is all ready well known by those listening and you must present the best possible rendition.
3. Accompanist - Make certain to practise with the accompanist so that speed and volume do not become negative issues. Your accompaniment must augment your vocal sounds not drown them out or be so soft that it is hard to stay in tune.
4. Tried and True - Please, oh please stay with the original and straight forward rendition. There is NO need to warble or use rubato to fancy it up. An anthem is not the time to get creative. This is especially true when the audience is encouraged to sing along. K.I.S.S. the anthem (keep it simple sweetie)
5. Dress Appropriately - It may be hot or cold. It may be an arena or board room. Wherever and whenever you sing, please wear something that reflects the importance of your song. Choirs who have set uniforms are set. I believe groups sing better when they dress to reflect the sound they wish to make, blended. The old white top and black trousers or skirts is always a good fall back. Soloists, please cover up all your parts and let's not have a wardrobe malfunction.
When in doubt let the babies sing it.