Well, I'd first say that you are an awesome Dad for getting your family into this sport and taking on the responsibilities and expense of owning a boat.
You are doing the right things in general. Mark's books are invaluable. Time on the water in even more invaluable. A couple of other things to do are to invite some experienced guests on your boat and learn as much as you can by taking guidance from them. Hopefully they will return the favor on their boat and you can learn some more. There is no substitute for time on the water. Also, don't be fooled or intimidated by the reports on this board. Remember that some of these posters are extremely experienced fisherman and have spent many many years running their own boats to get to this point. Also remember that many of us only report on our more successful trips which is understandable but also can make things a bit tough for a newer guy who assumes these guys always nail'em every trip out. It's not true for all but a very few of the best...who do actually nail'em virtually every time out...and I ain't one of them

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You can also do some six-pack or small boat charters with operators such as John King aka Afishinado in Avalon, Mark Wisch at Pacific Edge, The Dreamer, The Old No 7, The Tonnage etc. All of these operators are outstanding fisherman and you can learn alot more about fishing on a small boat charter than you can on a large sport boat. Alot of good fisherman won't admit to it...but they've done these kinds of charters along the way (or found other ways to bum rides like deckhanding etc.) with these boats to learn. As a paying customer, it's not a cheap way to learn...but it's effective.
976 tuna is an expensive proposition at first blush...although not as expensive as it seems when you consider what your other costs of ownership are. Many many people trash the service and say the dope is old/dated/rehashed/misleading/secondhand blah blah. I can't say much about it except probably for Catalina which I know fairly well in terms of where the bite is at any given time. You know what...the 976 dope ain't too bad. In fact...it's on point quite a bit albeit it can be little dated sometimes. They've got some charter guys who are clearly giving them straight reports whether they want to admit it or not. Whether it's worth the money of not, only you can say. And I can't begin to speak to the quality of their other info i.e. offshore etc. In terms of the specificity of the info, they post #'s so it's quite specific. If the subscription got you one good trip a year that you otherwise might not have, then maybe it's worth it to you.
Unfortunately, the #'s are only one part of the equation...and are really the easiest part. The harder part is figuring out when the conditions dictate that you fish one spot versus another. After all, you have hundreds of spots to choose from at Catalina alone...thousands actually. Why one versus another on a given day? How do you know when to fish a spot? It's conditions (current, tide, moon, water temp, etc. etc. etc.) that tell you that. And that's what the pro's are really really good at...reading the conditions at the spots to know which one to pick. And no internet site or subscription board will give you that. By the time you see dope on 976 and get to it, the conditions are totally different and so will be the fishing... So, you have to learn how to read conditions and I can tell you from personal experience that only time will help you learn that...I've got a lifetime to go.
Time, experience, building your own library of stock spots that have worked, keeping a detailed log-book to refer to in the future as to what conditions prevailed when a spot produced (I'm way too lazy at this one), building a small network of friends you can rely on to help...and be helped, going to seminars to hear people like Mark speak or Freddie Hollander (Fish the Tides Freddie), watching the internet boards...it's all pieces in a puzzle which will add up to you getting fish on a more consistent basis over time. Be patient as it takes years and years.
As an example...Mark has been doing this for only about 46-48 years or so! Sorry to date you Mark.
Best of luck to you!