Well, I posted my pics with the hope of gaining some credence for what I have to say on the topic. Just to give you some basic information, most of the measurements you read about in the magazines and online are bullshit. Nearly all of the pros exaggerate their measurements, and most people online also exaggerate a tad. This really would be no big deal except for the fact that it creates a sort of arm dysmorphia. In other words, I have seen posts on this site that a 18" arm is no big deal. Well, if that arm is all fat I suppose it isn't, but if it is a muscular arm that measures 18" or more, cold (not pumped), and at a right angle to the bone of the upper arm, that is a big stinking arm! Arm size has a lot to do with bodyweight. The biggest pros of today who weigh 275 lbs + in the off-season obviously have 18" plus arms, some of them getting over the 20" mark. Not as many of them have arms that measure in excess of 20" as claimed, not nearly as many.

Ok, enough preaching, let's get down to how one gets big and strong arms. I would like to think that I know a bit about this as I have arms that have both good size, and good strength (check my journal for more info.). Now, I do not base my ideas only upon myself, I have 4 good friends who have/have had 18" + muscular arms (plus myself, at my largest my right arm measured just under 19.5"). Of the 4 mentioned, 3 of them had arms that measure(d) in excess of 19" (cold, properly measured). For you forearms freaks, I have 2 friends who have forearms that measure(d) in excess of 15" (cold, properly measured).

Wait, I did say I would get to it, didn't I? Ok, let's roll. Of the guys mentioned above, not one of them (including myself) performs more than 5 hard sets for their biceps and triceps. If you didn't read that last sentence slowly, read it again! Each of these men perform 5 sets (not including warmups) or less for their biceps and triceps. Why is that? These men train with intensity, they take each post-warmup set to failure (concentric---positive failure---or beyond). They train using 10 reps per set, or less. They train as heavy as they are capable of, and they constantly try to increase the amount of weight they can handle, or the repetitions with the same weight, or both.

When I first began weightlifting, 14+ years ago, I read Arnold's Education of a Bodybuidler. I also got my hands on all of the muscle magazines I could, and devoured them. It will not surprise you to learn I was soon doing 5 sets per exercise, 3-4 exercises per bodypart, 5-6 days per week. I got bigger and stronger. I didn't keep getting bigger and stronger for long. My weight plateaued at 180 lbs (I am 5'11"). I couldn't get any bigger, and I wasn't getting any stronger. By this time, I not only would buy all of the magazines, I would go the bookstore at the mall and buy all of the bodybuidling books (the internet was a relative non-factor back then). Luckily, I came across a book called Super High Intensity Bodybuilding by Ellington Darden PhD. This book, and many others by the same author, opened my eyes to
the world of low volume, high intensity training. I decided to dramatically alter my routine and reduce the volume considerably (I was already training intensely). Wonder of wonders, I started to grow almost immediately, and I kept growing.

Ok, let's summarize how 5 people I know well (including me) got big and strong arms:
5 sets or less for bis and tris, taken to failure (or beyond)
low overall volume for the entire body
10 reps or less per set

If you want big and strong arms, there are only a few keys needed for your success. For most people, I recommend 3-4 sets to failure (post warmup) for your bis and tris. I recommend you perform the first set to failure for low reps, 2-4. For your next 2-3 sets, I recommend 6-10 reps to failure. Without getting too wordy, you need to mitigate the frequency of your workouts in order to allow for complete recovery between workouts. Too many people get set on training specific days of the week, without regard to whether or not their bodyparts have fully recovered between sessions.
These are the same people who never get any bigger and stronger. You know them, they are the bulk of the population at your gym! Don't let this happen to you!

Nutrition is important, but not in the manner you think. Nutrition is important with respect to how much you eat, not as much what you eat. You need to consume adequate calories to allow for growth to occur. How much you need to eat depends on you and your unique metabolism. It is very age dependent. Younger men (23 and below) with quick metabolisms will need large quantities of food, older trainees, or trainees with slower metabolisms will not need nearly as many calories, and will only get fat if they overeat. The younger, quick metabolism, trainees need not pay a huge amount of attention to the makeup of their calories. Older, slower metabolism, trainees should pay closer attention to the makeup of their calories, comsuming relatively higher percentages of proteins and carbs, and lower percentages of fatty foods.

Big and strong arms will not come overnight, however, they will come quicker than you think if you follow the principles I have mentioned above. There is one more very important factor, overall body size. If you want big arms, you must train your entire body. Training your legs properly (same basic principles as above) will help to ensure your ownership of a pair of big and strong pythons! Don't neglect your legs!

Follow the principles above, don't get confused by all of the flavor of the month routines, and you will be bigger and stronger than you ever imagined you could be!

p.s. If you want more on this topic, let me know and I will write a more extensive article with specific routines, calorie counts etc.