Unless you are some sort of savant, the only way you can get good at doing anything is to practice. Once you have practiced just about anything enough, you will get pretty good at it... You might not ever be a Rembrandt, but usually passable.
Once you have acquired the skill, it doesn't stay with you, you have to maintain it as well. What does that mean? Why, more practice, of course. The more, the better. But do you ever have one of those days? You know the kind I'm talking about...
The old saying is that it's like riding a bike. Once you learn, it does go faster to "re-learn" the skill. But it does take time, none-the-less. At the same time, it's easy to forget things - like why I hate using pine for practicing dovetails. I had a set of rather utilitarian drawers to do and thought that since it had been a while, it would be a good opportunity for some practice. I grabbed some pine I had on hand, and went to work practicing (I always like to make a few practice cuts before tackling the real thing.
It was miserable. I couldn't do it for squat (see above photo). Why? I'd forgotten that pine, while ubiquitous in construction, is a horrible wood to work with a chisel unless you have it killer sharp, and even then...
Well, then - I re-thought my "practice" (and sharpened my favorite paring chisels) I ditched the pine and dug out some beech and went straight to work on the actual drawers themselves. I figure, well - why not practice on the final pieces themselves? What doesn't work will just have to become firewood. I have a lot of firewood, you must realize...
Things worked out much so much better after switching to the hardwood. Construction grade white pine can be such a difficult wood to work with, depending on what exactly you have. Yellow pine, fir, hemlock, and premium grades are leagues better to work with - but the stuff I had here was horrible.
I still made several mistakes using the hardwood - not so many in the execution of the cuts, more so along the lines of cutting along the wrong side of the line. Even after marking the waste with an "X" . Ugh - what a dope. I'd even be saying "cut the waste side" to myself, and still do it wrong. Remember, I'm the kind of guy that spends 10 minutes looking for the pencil I just put down that is right in front of me.
Cutting dovetails is a fairly simple task, but you have to visualize what's going on with each corner, and I swear I'm dyslexic on this stuff. If I were doing it enough, this probably (probably! yeah right) wouldn't be an issue - It wasn't too bad I was done, there were four extra pieces of firewood - not including the pine, BTW.
Procedurally, I guess I'm a "pins first" kind of guy - in reality, this matters very little, I've done it both ways and it's the same procedure each way. I don't use a set angle for the dovetails, I just use what I think looks "right". I don't believe any of the old timers were too worried about it either, from all the old furniture I've seen.
I start by numbering all the corners with a pencil mark (1-4) and layout the pins by eye (I might use a mark to guide placement, but I'm not worried about being exact). Using a marking gauge set to the depth of the wood I scribe the depth onto the end of all the pieces, and lay out the pins. Once the pins are cut, I use an awl to transfer the pin pattern to the mating tail piece.
I find that an awl is less likely to wander along the grain than a knife, giving me a more accurate line. Once the pattern is scribed, I darken the lines with a sharp pencil and mark the waste with an "X". The "X" is important (though won't fix your own stupidity - see above) to help you keep things straight as to what goes where.
As for darkening the lines - no matter how good the light is it can be tough to see a scribe mark, so the pencil line aids you in that respect. I might use a pencil alone, but the scribe is more accurate and it gives you a place to put the edge of your chisel should you need to pare any extra material off you miss when cutting.
I'm pretty good at sawing to the line, but to cut out the waste, these days I usually use a coping saw. I used to chop more, but find I do less damage if I cut it with a saw. I do really need to get some decent coping saw blades one of these days, though - I'm still working through a stash of blades I've had for 20 years that are pretty horrible at cutting straight.
As a result, I stay short of the line and pare the rest away with a sharp chisel. I never pare across the entire width of the piece, I work from each side to form a pyramid then work that pyramid down - here's an animated gif that kind of shows what I'm talking about (it sometimes doesn't work in some browsers, so be warned):
I pare down the waste from each side, with the last cuts being in the very center of the board. Having a very, very sharp chisel is key - for paring, I have 3 or 4 chisels I use ranging in size from 1/8" to 5/8" or so that I keep sharpened to a 25 degree angle, just for paring.
Once the paring is completed, it's time to fit the pieces all together. Most of the time, it takes a little persuasion to get them to fit together. Not too much - usually I can use my hand to hit them together, though on occasion it takes a few taps with a mallet to drive them home. Always use a scrap of wood (I have lots of pine - see above) so as not to mar the drawer, and don't use too much force - if it's not going together easily enough, that means there is more paring to do.
I usually don't do drawers sides that are this thick - most of the time, I prefer the sides be 1/2" thick or so. They require a channel be routed in the side where they will hang, so I used a thicker side. This particular set of drawers is fairly utilitarian, so I'm not too worried about aesthetics, just a strong joint. Some wax is all that is required to keep them lubricated.
A 1/4" channel is routed to accept the drawer bottom (made from 1/2" plywood - you can see the gaps in the dovetails in the photo above from the channel). Also, since there is no face frame in the cabinet where they are going, a false front is simply screwed onto the box after placing the drawers into the cabinet, allowing the fronts to be fit with the drawer in place. Nothing fancy, that's for sure - but certainly serviceable.
Really, I could have just machined these joints, but dovetails are a much stronger joint. Besides I needed the practice (as you can tell!), and this was the perfect opportunity. Am I repeating myself? It's just practice. Really...
Now - where'd I put that bloody pencil?