I am not going to do an actual tutorial myself because they are already out there. I will just direct you that way plus add a few comments from my own experiences.
You can go here and here. The first one also has the link for the armhole pattern.
It is hard for me to judge whether or not you will find the instructions manageable since I have already made them on my own without instructions. I do promise that once you make one and shake off the rusty feeling, then you will want to do more! They really can be easy, as far as sewing clothes go!
Here are my some of my random thoughts about the whole thing:
* Using pillowcases can be the easiest way to start out because it is less initial sewing. The sides and the bottom hem are already done for you! I bought a bunch of vintage pillowcases at a flea market one time (for like a $1 each!), made them look crisp again, and have them to use. You could also just buy a plain pillowcase of your liking and add decorative trim to the bottom, as well as appliques to the dress.
* The latest dress I did was from material, so I had to sew up one side and the hem. I actually sewed both sides just to make it look the same, but you don't have to. Some recommend turning the one seam to the back.
* This was the first pillowcase dress that we received. These can be a pretty easy sewing experience because the "shirt" part is already done for you which means no neck or armholes to do!! You can do warm or cool versions. I have done a few myself, including one for Christmas with a cream top and nativity fabric and one for Fall with a black top and pumpkin fabric. You can use a pillowcase or fabric. Basically, all you do is trim the shirt, pin the fabric to the shirt hem, and sew on the fabric. You will have to do some gathering of the fabric first before you pin and sew. Do you know how to do that? I also have used onsies which meant you did not cut the fabric because you still want to utilize the onsie snaps.
As you can see, she went pretty high with the pillowcase (she used an actual pillowcase), but you can go as high or low as you want when adding to a shirt. She also added some tulle and a ribbon, but I haven't done that myself. Just a matter of pinning the tulle at the same time you pin the case or fabric on.
* I have also sewn a version using two tea towels. It turned out super cute but I can't find a pic to download right now. Just sew up the sides and proceed with arm and neck holes as directed. Hem is done for you!
* Oh, you could also do a cute version by cutting off the bottom of some overalls that have been outgrown and adding fabric to the bottom!
* Armholes always drive me crazy! My best advice is just be patient and make enough snips in the fabric to allow pinning and sewing to be as easy as possible.
* I think at least one of those tutorials talk about using elastic around the two neck parts, but I don't do that and don't really see a need. Once you thread the ribbon through, you are gathering the fabric around the neck hole anyway to make that look.
* The second tutorial goes into a lot of detail about the armholes, but I don't do that either. The dresses are usually just for my dtr and I am lazy. I basically do 2, 1/4" folds all the way around the armholes, snipping and pinning as I go. I snip some while folding and sometimes a few after pinning. By snipping, you are allowing the material to lay down nice around the curves and it makes sewing easier without a lot of gathered places. Does that make sense?
* Length and type of ribbon depends on the look you want. You can go skinny, fat, grograin, tulle, whatever! You do want the ribbon long enough to allow for gathering and to allow for making pretty bows.
* Except for this last one (because I didn't have enough fabric), I typically make my dresses so that they are pretty long. I just love barefoot girls with long cute dresses! Plus, then they can likely use them for several seasons and even add them over leggings or jeans later on.
I also found a place where you can purchase them at this website. I will tell you that my personal opinion is these dresses and outfits are overpriced for my liking. But she does have a couple of sale sections that are good if you can catch dresses/outfits before she sells out.
Does that help at all?
I promise you can do it! If you want to practice first before using a pillowcase or fabric that you adore, start out with a cheap pillowcase and do a trial run!!