On a cup of (non-pagoom) wine you will say four berachos; on the wine, then on the b’somim, then on the firelight and finally the Havdalla beracha. Some say it is a mitzvah d’oraisa. (ShA 1 – MB 1)
The pesukim that are customarily said before Havdalla are for a siman tov. (Rama 1)
Keep your eyes fixed on the kos in order to concentrate. (Rama 1 – MB 3)
When filling the kos with wine, let it overflow a little bit for a siman beracha at the beginning of the week. Pour some more wine and extinguish the flame after you drink from the kos. (Rama 1 – MB 5, 6)
Sit for the drinking. Drink the entire cup so you won’t be in doubt of a beracha achrona. Normally, we don’t share the kos Havdalla with all members of the household. (MB 6)
Women have the conduct of not drinking from the kos Havdalla. (MB 6)
Rinse your eyes with some left over wine – it shows endearment for the mitzvah. (Rama 1)
Wine is l’chatchila. Otherwise chamar medina or any drink that people drink all year around with the exception of water and borscht – those aren’t chashuv. Milk and oil are not used enough as drinks to qualify for Havdalla. (ShA 2 – MB 8, 9, 10)
Use whiskey only as a last resort, and then be sure to swallow a m’lo lugmov. (MB 9)
There is a minhag to say Havdalla on beer Motzo'ay Pesach since the beer is choviv at that time. This only applies in a medina where people always drink beer. (Rama 2 – MB 12)
If someone is saying Havdalla over chadash beer and you consider it ossur, do not be yotzay with him. If you consider chadash only a chumra, you can be yotzay with him. (BeH “im”)
What if you have no mashke for Havdalla, are you allowed to eat? If you expect to get mashke only after midday on Sunday, you may eat. But , if you expect to get mashke before midday, you should be machmir and fast until then, unless you are a weak person. (ShA 3 – MB 19, 21)
If you will be eating before Havdalla al hakos, make sure at least to say Havdalla in Shemoneh Esray. (MB 17)
Here is the procedure for Havdalla:
Everyone sits down to be yotzay bikvius. If your minhag is to stand to escort the Shabbos, at least invite everyone to stand at attention.
Hold the wine in your right hand and the b’somim in your left while you say Hagoffen.
Switch hands (do not put down the kos) and say Boray Minay V’somim.
Release the b’somim
Look at your fingernails and say Boray M’oray Hoaysh.
Take the kos back into your right hand and finish the Havdalla. (ShA 6 – MB 27, 30, 31)
Even if you were already yotzay Havdalla in shul, you can repeat it to be motzi someone at home who has not yet heard Havdalla – even for a boy of chinuch age. (MB 32)
Are ladies obligated in Havdalla? There is an argument. Therefore they should hear Havdalla from a man who is definitely obligated. A man who was already yotzay should not say Havdalla for a woman – it might be a beracha l’vattala. (ShA 8 – MB 36)
When a lady says Havdalla for herself, she should drink the wine as well. It would seem proper to omit the beracha Boray M’oray Hoaysh. (MB 35 – BeH “lo”)