Flows & Checklists
Most GA instructors do teach their students to use checklists, but they are most often taught as "do-lists." In other words, as you read each item, you flip the switch, adjust the knob, or read the gauge that it directs you to. This can be cumbersome, as your attention is continually flitting between the checklist and the instrument panel, and longer checklists can take a long time to work through. Many pilots stop using checklists as soon as they have the procedures memorized and they're out of their instructor's watchful gaze. When I was an active CFI, I found that advanced students who'd been flying on their own for long had to be cajoled and threatened into consistent checklist usage.
At the airlines, the desire to keep one's job provides ample motivation to use checklists and comply with the other dictates of standardization. Fortunately, we have a pretty good system of checklist usage. They tend to be fairly short given the level of complexity in our cockpits. If it's not important, it's left off the checklist, and if a number of switches can be grouped into one item, they are (de-ice boots, prop anti-ice, pitot-static heat, and windshield heat are all grouped under "Ice Protection," for example). Furthermore, checklists are actually used as checklists, not do-lists. You first configure the airplane appropriately for the stage of flight and then read the checklist to verify that the listed items have been accomplished.
"But wait!" you protest. "My instructor told me not to memorize the checklist!" Well, your instructor told you that so you wouldn't ditch the checklist the moment he was out of the plane! If you're using the checklist to verify everything, it's perfectly acceptable to accomplish the procedures by memory. At the airlines, we memorize every procedure for each normal stage of flight, on airplanes considerably more complex than the average light plane. Now, the best of us occasionally miss items, but that's what the checklist is for. Another tool we have to help us remember the procedures are flow patterns.
A flow pattern is simply a logical pathway across the panel or panels that will guide you to the systems that need reconfiguring for each phase of flight. Each phase of flight will have a different flow pattern, but they often follow roughly the same order. Here's a picture of the First Officer's "Before Start" flow pattern on the Megawhacker:
If you asked me to name each of the fourteen items that the Flight Standards manual says I should accomplish before start, I could rattle them off to you - not because I memorized a list of procedures but because I can visualize the flow pattern and know which systems it leads me to and in which order. Obviously, this works only because the flow pattern follows a logical, linear path. If it had me jumping all over the panel, it'd be worthless and I might as well remember the procedures by how they're listed in the FSM.
The airlines have full-time flight standards people to put together and revise flow patterns, procedures, and checklists. You can do it for the airplanes you fly, though. You can develop your own flow patterns, checklists, or both. The goal is to come up with something that you like and that you find easy to use consistently, and keeps your eyes out of the cockpit for more time than the system you're using now.
You'll typically design flow patterns for the following phases of flight: before start, after start, before takeoff, after takeoff, approach, before landing, after landing, and parking. I suggest you work out the flow patterns either by sitting in your cockpit or using a high resolution picture of it. For each phase of flight, trace an easy-to-remember "trail" that connects each item that needs to be checked or reconfigured in an order that makes sense. Memorize each "trail," thinking about which items you would be touching, checking, or moving along the way.
Here's a sample Before Start flow I put together for the Cessna 150:
You start at the lower left corner of the panel with the master switch (turn it on) and work your way counterclockwise. This directs you to the electrical panel (CBs in, lights as required), trim (set), throttle quadrant (throttle & mixture set for altitude & type of start), flaps (up), radios (off, ELT armed), flight instruments (clock and altimeter set) and finally back down to the lower left corner (prime as appropriate, then in and locked). You would then read a simplified Before Start checklist that ensures the major items for the start have been accomplished.
Primer--------------IN & LOCKED
Note that this checklist says nothing about flaps or trims even though it's in the Before Start flow. That's because you'll also be checking them in the before takeoff flow, and then they're in the Before Takeoff checklist. You keep the checklists short and usable by including only items that are applicable to that phase of flight, even though you may be taking care of "housekeeping" items ahead of time in the flows.
The C150, like most smaller piston singles, is simple enough that you can use the same flow pattern for most phases of flight. For example, imagine how the above counterclockwise flow would cover approach items: lights set as appropriate, mixture set for density altitude, ATIS received and radios set, altimeter and DG set, primer in and locked.
I remember using an abysmally long before start checklist for the PA28 that was actually a do-list and went so far as telling you, step by step, how to start the engine. The engine on the PA28 really isn't that complicated to start - you don't need to include simple memorized procedures like this on your checklist. Now, there may be more complicated variations that you don't use often - hot or flooded starts, for example - and it's perfectly acceptable to include these on your checklists as designated do-lists.
Certain time-critical emergency procedures are memory items both in GA and at the airlines. For an engine failure at low altitude, for example, there is a procedure you should have memorized and be able to execute within seconds. These memory items should have associated checklists that can be accomplished if time permits to make sure that the appropriate actions were taken. Any emergency checklist that does not back up a memory item should be used as a do-list. If you don't have a good emergency checklist for your airplane, make one - the emergency checklists in the Pilot Operating Handbooks are typically inadequate and usually inaccessible anyways. Keep yours in a handy place and make it visible - I suggest pasting the checklist to hot pink card stock and laminating it.
Flow patterns and checklists used as checklists aren't completely foreign to General Aviation: most of the structured Part 141 training programs use them from Day One, as do more progressive FBOs and independent CFIs. If you've never used this method, I suggest you give it a try. It makes good cockpit discipline a whole lot more palatable.