When I see someone else's fly box there is often a mixture of emotions that flood my brain. Sometimes a bit of envy, perhaps determination to make mine look as beautiful, sometimes ideas start flooding and I see my free time disappearing, and sometimes... I silently am weeping.
When I look into a box and see a row of Pheasant Tail Nymphs all tied to different proportions (some tails stick out 2 inches with 30 fibers and others have 2 fibers and are only a millimeter long, etc) the OCD in me wants to break down and give them my box. I recognize that no one starts out making flies beautifully, (and I have what seems like several thousand of my first flies to prove that), but this is one skill that's not really a skill as much as it is a discipline.
Make your flies mirror one another.
What I mean is, if I pick up two (or ten) of your flies of the same pattern there should be no glaring differences. They should look as similar as possible. Tail length the same, hackle size the same, body width the same, approximately same number of legs or tailing fibers, etc. cosmetically there shouldn't be huge differences between your flies.
I do have an exception, but I will get to that later.
There is one big reason why I think this is important other than just wanting my fly box to look good and photograph well, and another smaller reason.
1 - FLIES THAT MIRROR EACH OTHER PERFORM THE SAME WAY
I work to keep my fly patterns as similar as possible. I want to know what the fly should do depending on how I made it. For example, when I pick up an unweighted caddis fly I choose it because I want it to stay higher in the water column. If my proportions are different between every fly, say, one fly is tied with lots of excess dubbing and no additional weight another fly of the same pattern tied with no additional dubbing their performance will change. The fly with hardly any dubbing will sink a lot quicker because it doesn't have the "parachute" attached to it like the fly with extra dubbing does. The difference of surface area effects the sink rate, which then effects how I need to fish the fly.
Because I tie patterns as similar as possible I know that every unweighted caddis imitation should float or sink in the same way. If I need a little bit of split shot to get that fly down faster, every other fly like that in my box will require the same amount of split shot to be at the same depth.
If all my flies look different it will take me more time to adjust weight, which means less time fishing, more time confused.
2 - FLIES THAT MIRROR EACH OTHER PROMOTE CONFIDENCE
Even if you can't tie that well yet, focus on making your flies as best as you can, and tie them to the same proportions. This will help you quickly gain confidence with your tying. Confidence is weird because you can't really smell it or buy it, but it does help (or hinder) with tying. While you're creating something if you constantly second guess yourself and question your ability, the size, the color, or material that's going to burn you out pretty quick. And, the best way to get better at tying flies is... to tie flies. If tying becomes a sad time of disappointment pulling hooks off of the vice that you aren't happy with or proud of you won't want to fish those flies.
Do you best, take your time, and make them look as similar as possible - and those simple steps will help you leap frog your way into the fly-tying world!
TIPS FOR PROPORTIONS:
If you are just starting out and have never seen a mayfly on the water, much less created one, buy some flies from your local fly shop (or me), and tie everything to their standard. This helped me a lot when I was starting, and still to this day!
I often leave one finished fly on my bench so I know what standard I am tying the rest to. If I am feeling unconfident in my proportions I will check the fly I am working on with the finished fly. The reason for this is, I can see if I am off or just being mental which is about a 50/50 split most times.
Clousers are the perfect example because I often second guess myself on the eyes. How I combat that is, after I start tying the dumbbell eyes on I hold up my finished fly to see if my proportions are similar - if not I realign the eyes to ensure they match.
Also, Clousers are an excellent example of the importance of proportions. The action of the fly changes depending on where you place the eyes. Near the eye of the hook they will do a fast-paced nose dive, towards the center of the shank and they will drop almost laterally. Tie it how you want it to perform, but if you want the action to be the same the flies have to be the same.
EXCEPTIONS WITH PROPORTIONS
Weight. Two things about weight is 1) weight effects the body size of flies, making them a little thicker and 2) obviously, the addition of a bead head changes the fly shape/ proportions/ action. These two things, change the fly all together, which is why any time I put weight in a fly I treat it as a totally different pattern and distinguish how heavy it is by varying colored thread wraps.
Just be sure you know what has extra weight and what is unweighted, and make sure you put the weight on the same place each time!
Proportions are a minute detail in fly fishing/ tying. For a lot of people proportions don't matter, but it matters to me. In fly fishing I want every possible advantage I can have. Proportions are not a total game changer, but an extra tooth in the saw.