What is the most common error?  

Common errors

I would say the biggest problem I see in recipes is in organization. Length can be a problem too, but that is usually related to organization. You know that expression, "the bigger they are, the harder they fall" ? Well, that is true of chefs! Now there are some notable exceptions (Melissa Kelly, of Primo, in Maine, is one), but I have found that the more lauded, famous, "genius" chefs tend to write the absolute worst recipes. This doesn't reflect their food, you understand, only the way they try to communicate how they cook it. Why is this? Think about how they work -- in large commercial kitchens with a large staff doing prep work, cleanup, etc. In a restaurant kitchen many things are happening at once. Now imagine translating a recipe to serve 150 (or even 40) to serve four people, and it will be prepared by one person. Consider that professional techniques have to be described to a home cook who has probably never taken cooking classes. Now also think about how this recipe has to fit in a small space, using as few words as possible. This is where the recipe tester/recipe editor(s) come in.

Chefs' training usually doesn't include recipe-writing for home cooks, so it's no surprise that their written recipes tend to need a lot of work. But these days chefs can easily become celebrities whose written recipes are highly desirable. A chef who can't write a recipe is like a celebrity who needs a ghost-writer. I would say that young chefs should begin writing for home cooks early in their careers so that they can continue to relate to them after they are stars.

Amen! I can't tell you how many times I show up at a kitchen door with pad & pencil in hand asking for ingredients and techniques.
A couple of weeks ago I directed a food stage and the majority of the chefs were from out of state, made showing up at their kitchen doors more difficult....one of the recipes had 75+ ingredients, I did not test nor edit too much figured anyone that wanted to tackle a $150 for 4 serving recipe could figure out his exacting directions that were written ala Kellerisc.

Calculating measurements

Some people have a talent for recognizing measurements just by looking at them or feeling their weight. I think this is true of people who constantly cook from recipes -- after a while, you just know what a teaspoonful looks like, or what a pound feels like in your hand. But it's harder when you are cooking without a recipe and adjusting ingredients to taste as you work.

It's very nice to have your own recipes written down, even if you aren't hoping to publish them. When you want to share them you'll have them handy, and they'll be passed along (hopefully, with your name on them) and bring pleasure to many people. You can ask a friend to watch you and make notes as you are cooking a recipe, or you can make notes yourself. This is what I do as I am developing a new recipe: I go slowly and measure (or weigh) each ingredient, including spices. First write down your basic recipe without the quantities, and leave lots of space on the page (double or triple space). Fill in the known quantities (3 pounds lean ground beef, 4 green bell peppers, 1 medium onion, etc.). Don't forget to note specifics about the ingredients (85% lean, finely grated, peeled and sliced...). Add seasonings gradually. If you add a teaspoon of oregano, note that on the page. If you decide to add another half-teaspoon later, make another note. You can do the math later on when you re-write and edit the recipe. I usually write in pencil if I expect to make a lot of changes to a recipe, or in red pen if I am correcting a recipe I am testing.

I know it's annoying to stop and measure as you are cooking if you aren't used to it. But it needs to be done only once for each recipe, and then you have a permanent record of your work. I keep a book of hand-written recipes and I treasure it. It reminds me of family favorites, gives me a quick reference for ingredients, and my notes on each recipe reminds me of where it came from or who especially loved it. Because my book means so much to me, I made my children similar hand-written books, including favorite recipes of theirs that were not in my own book, and leaving them space to add recipes of their own.

Denise, this is exactly how my mother managed to get a written recipe for my grandmother's challah. She had my grandmother make it three times, under three different weather conditions, noting the amounts as she went. For instance, when my grandmother spooned sugar into her hand, my mom "stole" it and checked it with measuring spoons before adding it to the mixing bowl. She did the same with flour, oil or butter (depending on if it was for challah or for sweet rolls), etc. I now have my grandmother's recipe, and when I make it, it's like she's standing beside me. I thank my mom often for taking the trouble to do that for me.