First of all, take some measurements. Measure your waist and then from your waist to wherever you would like the skirt to sit on your leg (I usually go for an inch or so above the knee.)
Get your fabric and place it on a flat surface. For the waist, depending on how puffy you want the skirt to sit you can double or triple the measurement taken (the bigger you make it the more puffy the skirt.) I usually double mine up, so if your waist measures 28" for example, then make the fabric 56". If you don't think your fabric is wide enough for this, don't panic :) you can always have two pieces of material and attach them together to make the desired width. Now use the length measurement and mark that out as well, then cut out the desired size.Â
For the elastic, I think a wider piece sits nicer so I tend to use the 1" stuff. Take the original waist measurement (28") and add another 1". This means I am cutting a bit of elastic out to 29". This 1" extra means you can sew the two ends together to secure it in place.Â
Now take your cut out fabric, fold it in half putting the 'right sides' (the pattern of fabric you want to see as the front of your skirt) facing each other. This means that the 'wrong sides' are facing you. Sew down the open side (or sides if you are using two half bits of fabric) like so...
Now you will have a tube shape, turn the fabric so that the pattern or 'right side' is now facing you. Give this a quick iron to make sure everything is sitting flat.
We are now going to sew the 'casing' (the bit where the elastic will sit around your waist.) So fold half an inch inwards towards the inside of the skirt (you don't want to see the fold from the front) and iron that flat, then fold down another inch...then again iron it down flat. Measure your elastic against it to make sure there will be enough room for it to sit in this fold. When you are sure there is enough room, sew this fold leaving a small gap like so..
Thread through the elastic (I find it easier to do so if I attach a safety pin  to the end that is being fed through the gap) until it is sitting neatly in the casing you have just sewn. With each end of the elastic in hand, do what was said earlier on and sew the elastic together with a 1" overlap. Once you are sure the elastic is secure together, sew up the small gap in the casing.Â
Almost done now! Last thing to do is the bottom hem of your skirt. Take your iron and do the same thing as you did with the elastic casing. Fold half an inch in towards the inside of the skirt and iron that down, then fold another half an inch and iron that (ironing the skirt throughout just makes for a neater finish and saves you using any pins!) When you are happy with your hem (my 1" hem is an example, you could hem it smaller or larger if you like) then sew away!Â
Tidy up any loose threads and then that is you done!!! My first skirt took me closer to an hour to make, now they only take half an hour... practice makes perfect. Happy sewing & remember if you have old fabric lying about the house, use it!!Â