I chime in on a coulpe points.
Being observant is one of the most important things in being a good fisherman. Notice every single minute detail.
When I hook a fish no matter how big or small, I now automaticly make a mental note of all the variables (tide, time, depth, retrieve, did I let the lure sink while clearing fouled line before retriving, speed of retrieve, contoure of bottom etc)
Then there are smaller things to pay attention to. Smell, the "look" of a piece of water, birds behavior (not just working but direction of EVERY passing bird.. they are not going on vacation)
Spending time OTW is critical, by fishing more you will automaticly do things that now you may have to think about doing. THe list above of things I make note of along with many others, now just kind of happens. My mind just proceses these things without concious effort. In doing so I find I can "see" good water that others don't always see.
An example is when fishing a large school of breaking fish I don't jsut cast to the school. I observe it, notice where the heaviest concentrations of fish are in the school (even in the areass of heavy activity there are always pockets of slightly BETTER activity) I pick the school apart rather than fishing "the whole school" When I cast to the school I cast to a specific boil or fish almost every time. If nothing else its accuracy practice, but I believe it helps me catch a few more fish than someone next to me casting randomly at the school.
Always believe you can catch more fish. If you are catching a fish every other cast you can do better.... and you should! Never be satisfied with anything but a fish on every cast, then work for bigger fish every cast. In a frenzy of feeding why are you catching every other or every third cast? In another way of saying it, your catching 30-50% of the time... remember below 70% isn't a passing grade

So every third cast sounds good, but 30% sound lousey, fix it.
Be willing to change things to catch more even when your doing well. This is where time OTW helps. If you only get out 1 time a month and your in a blitz catching every 3rd cast, changing things may not be easy and may not be the right thing to do since your time is limited. If you fish daily know you can do this again soon and if you can dial things in you'll do even better next time.
Don't complicate things! Fish are not smart! They are instinctual, but not smart. They have certain urges/need and they work to meet them. Those needs are:
A. Eat
B. Breed
C. Don't get eaten
D. Try to be comfortable doing A-C
Thats really all most fish ever do. figuring out how they are doing this is what fishing is all about. Its not outsmarting the fish its learing about them and adjusting your methods to meet those needs.
I've fished for new species I've never fished before and by using this method Ive been able to find and catch types of fish that were unlike what I'm used to.
Also learning how others catch similar types of fish can help you catch you type of fish more effectively. Examples are: they fish eels for cruising cobia, I read all I can on it so I can better learn to fish eels when fishing cruising bass. Even though we don't have cobia around, the techniques can and do often overlap. THen when you find yourself in an area with cobia on vacation, you've got insight on them and can and should be able to find and catch them.
The bottom line is pay attention to details no matter how small.
As for fishing with the guide, thats a tough one. I generally don't like to fish with my sports unless it's discussed when booking the trip. I don't feel I pay enough attention to my sports when I'm paying attention to MY fishing, so I don't like to do it. A good guide should be able to hear a loop in you line when you cast. Hear the line over the bail roller on the retrieve before you figure out what the problem is. Or unhook your loose flyline from something BEFORE the fish hits and breaks off. If I'm fishing those little things may go unnoticed and thats not fair to the guy paying $$$ for a trip. So if you plan to fish with a guide make sure you let them know before you get OTW that is your intention. JMHO.
Hope this helps.