My trouble is I get excited by openings, and keep switching when I know it would make more sense to stick to a simple repertoire and learn it thoroughly. I'm particularly susceptible to two kinds: the system openings which promise you the chance to play the same moves against almost everything your opponent throws at you, and the sharp trappy ones. I know that I should really be settling into a calm, not too complicated positional repertoire which would suit my style, but then some new guru comes along with a universal system or an opening that promises a win in the first few moves, and I fall for it again. I do enjoy looking at new openings and the ideas contained in them - and they probably teach me quite a few tactical and postional motifs in the process. But I never manage to acquire a deep knowledge of anything.
Did You Have Fun Building Your Opening Repertoire? Really? Teach me How!
Similar to SIowMove I approached learning and developing an opening repertoire in the most practical and fun way.
This is the practical and fun way IMO to quickly have a solid repertoire:
1) Figure out pawn structures or openings you feel comfortable in. Additionally, pick openings that have similar pawn structures from e4 to d4. Example, Caro Kann and the Slav both have the c6 d5 pawn structure. The Pirc and KID compliment each other well too.
1b) To take this a step further or as another alternative I suggest picking lesser known openings that provide you a psychological advantage from the first few moves. From the beginning of the game your opponent is now in your home territory. Examples, e4- Rossolimo, KIA french, Grand Prix Attack ///Black - Scandinavian, Nimzowitsch Defense, Alehkine's Defense, Benoni, Benko, Dutch.
2) Once you pick openings that you feel comfortable in or appeal to you. Look through a few grandmasters games on chessbase.com or chessgames.com. Get a feel for where your pieces and pawns go. You don't have to spend much time here, just get a general feel.
3) Now the fun part. I use to HATE... I mean HATE HATE HATE bullet chess. But now I've grown to love it and use it to improve faster! *gasp* Speed chess makes you worse, not better doesn't it?
No! Provided this one stipulation: you immediately review your games.
So, play bullet games and after each one, review the game using chess.com's analysis and see where you didn't play the best move. You will soon know the best lines inside and out.
It is more practical playing bullet chess over other time controls because it gives you more opportunities to expose you to your new opening repertoire.
15 minutes in time:
15 min game = one exposure
Bullet games = 5 exposures
You will very quickly become more comfortable in your opening repertoire than you ever had been before!
You will receive some beatings along the way. Don't worry! It's a part of the process. Don't get fixated on winning. You're goal is to improve your openings and get more comfortable in the positions that rise from them. It's also better to lose points in bullet than in standard chess or even in a tournament.
This is simply the best use for your time, the most practical and as you asked... the most fun 
Now the fun part. I use to HATE... I mean HATE HATE HATE bullet chess. But now I've grown to love it and use it to improve faster! *gasp* Speed chess makes you worse, not better doesn't it?
No! Provided this one stipulation: you immediately review your games.
So, play bullet games and after each one, review the game using chess.com's analysis and see where you didn't play the best move. You will soon know the best lines inside and out.
It is more practical playing bullet chess over other time controls because it gives you more opportunities to expose you to your new opening repertoire.
It's okay for you to play the Orpheus of Bullet, but to drag someone else down into the underworld like Eurydice is another matter. I wouldn't be caught dead playing Bullet, which elevates the shallow and denigrates the deep, but instructor Dan Heisman says that traditional Blitz can be used for exposure to different openings and implementing the method you use for learning what does and doesn't work.
it's like a tactics trainer for openings
not a substitute for brick and mortar, blood and sweat, work on openings but it is fun, free, and easy to use
All I see at Chessable.com are books that can be downloaded, both free and for a charge. Perhaps you can elaborate on what you mean.
it is very similar to a tactics trainer session where to do a bunch of problems and then log off to study other things
i'm very new to chessable and i have refrained from "studying openings" as so much advice to beginner players was to adopt "opening principles" and "work on tactics"
my problem was spending so much of my clock to just survive the opening (even in 30 min rapid) that is was tough to get past this stage
my coach recommended chessable as i was always having trouble placing my light square bishop as white out of an e4 opening - Bc4 and Bd5 would get me in trouble as i didnt know what i was doing other than "develop minor pieces"- drilling the opening of the italian game has given me some plans and ideas/goals to strive for after just a little work on the "book"- instead of treading water in the opening i feel like at least i'm doggy paddling
as a novice player the little work i have done on chessable has filled a void between my floundering application of "opening principles," and the proper/traditional opening repertoire development that much more experienced players do
Thanks Mr. Peterson for elaborating on what Chessable.com has to offer. Sounds useful.
Thanks for all the suggestions! I have adopted Bobby Fisher's philosophy with regards to having a chess opening repertoire. I read an article where he was asked how he prepared for his opponents. He stated he he only had a "few" openings which he liked to play or transpose into. He really bad-mouthed the idea that a person should have knowledge regarding many offensive and defensive openings and strategies. I have knowledge of only 3 or 4 openings depending on the color of the pieces I'm playing. My OTB rating is only 2031. However, I have had the privilege of playing 4 International Grand Masters. My record is 2 wins and 2 loses. This verified for me that my opening choices were sufficient for me. Good luck to all of us!!
My approach has been quite simple:
Learn the first three moves of your openings of choice. Why only three? Because it's just enough to get you out of the gate on good footing, and still not so much that you'll be overwhelmed.
Next: play a lot of games. Expect to lose a lot of games straight from the opening, but that's okay. You're not seeking wins at this point—you're seeking knowledge.
Stop after each game to analyze and review. This is key. Do not play a second game without first stopping to review the previous one—because your ideas of the game will still be fresh in your mind at this point.
Look at things first on your own, to see any mistakes you can spot. Then, turn on an engine and see what you might've missed. (In your case, focus mainly on the first 10 moves or less). Learn what you can. Rinse and repeat.
Over time from doing this, your understanding of your openings will begin to deepen, and you'll notice that you'll move from 3 moves deep in opening understand, to 4, 5, 6, to 7 ... etc. You'll have gained this knowledge from experience, rather than being spoon-fed it from someone else, so you'll understand the ideas behind your moves much deeper than one who has simple memorized them.
At this point, I'm usually about 10 moves deep into my openings while still being "in book"—even though I've never bothered to officially learn an opening past move three.
Additional step, if you're the kind who likes filing systems: Create a folder for each opening you play, and save any key positions or moves that you want to remember. Often these will be moves you've learned from blundering—and then reviewing to find the correct response. Keep adding to it and eventually you'll have your own opening repertoire tree.
Best of luck.