Except when played in a casino or online, bingo is more of a social than a gambling, event. As with any social event the key to a good evening is spending it with people whose company you enjoy. This can be a group of friends in your own house, at your local church, at a veterans' organization or fraternal group, and even, on occasion, at a volunteer fire house in a small town.
As organizations use the game as a fund raiser, most bingo nights are open to the general public, not just their own membership. Still, it is not unusual for more time to be spent socializing between games than actually playing, so if you don't have a group which you regularly play with, look around for one in which you will fit right in. A 70-year-old religious Catholic woman, for example, is much more likely to find that group at Holy Cross Church than she is at the local VFW hall where the men down a lot of drinks during the night and swap stories about their experiences in Vietnam or Kuwait.
When you go online, the socializing can still be a factor (although the gambling aspect is more important than it would be in your local church), so look for a site with a good community software function so that you can interact with your fellow players. They will help you with any "newbie" questions you might have and it is far from unusual for online friendships started in this manner to develop into "real world" friendships. Of course, as with any social networking site you should be very careful when giving out personal information or arranging to meet someone. While most people who use the internet for social purposes are fine, there is always the possibility that you will be running into a fake -- and possibly a dangerous fake.
Many online bingo sites offer sign up bonuses. These tend to be smaller than the bonuses being given at online casinos but this is offset by the fact that you usually do not have to put up any of your own money. Use these bonuses to research the various sites before deciding which are best suited for you.
Save your big plays for big jackpots. Watch the progressive jackpots to see where they peak. As the next peak approaches start buying more cards per game to maximize your chances of winning.
A larger number of players decreases your chances of winning but, at the same time, provides for bigger payoffs if you do win. You have to find a happy balance between the two concerns but, with a little experience under your belt, you should be able to determine how many players gives you the situation which you feel is ideal.