Playing online chess (not live), with at least 3 days per move is a great way to learn your opening of choice. I am not going to tell you what to study or not study, although I agree with others that openings are not as important as much as tactics and endgames are.
So if you are going to study openings, you should narrow it down to just a few openings because there are so many. For example, king or queen pawn as white and a defense for each of these as black.
Reference books are helpful, although now they have probably all been converted to databases, but the gold standard is the 5 volume ECO; the short version is the popular MCO (Modern Chess Openings).
Play over the games of masters featuring the openings you have chosen. Compare the opening moves in your games to the moves masters have played. Compare your moves to the opening references you have available. Make notes! Have fun!
Thanks for the great advice :)
Basically I don't go for a specific opening, although I am beginning to recognize patterns in an opponents moves (sicilian dragon, accelerated dragon, ruy lopez, kings indian etc). I don't know exact responses so I look at the board and counter threats all the while trying to open with principle. I am not just moving pieces from remembering how a ruy lopez or Scotch game starts etc. Sometimes it works fine and I can hold my own until we get past the first 10 - 15 moves, sometimes I fall for a trap. One thing I can say is that obviously I am learning as can recognize some of the patterns, as I said before. I also look see if there are any threats, opportunities for tactics etc. I might blunder by not taking more time to think, but I am trying to discipline myself and am making some progress. As long as I learn a bit more each time and make less blunders then I will be happy.
I'll never be a high ranked player at my age, but I am sure that I can improve to a level where I still enjoy chess and get to play players at a higher level without embarassing myself :)
One good thing is that I have plenty of time for study now that I am pretty much retired.