Here it goes..Its very simple..Once you get the hang of it its gonna be a piece of cake!!..
Cut a long strip of fabric, 2 and a half inches wide and 34 inches long.....the smaller piece in the picture was meant for another purpose ..I forgot to remove it while taking the snap..so pls ingore the smaller one.. fold the strip lenghtwise into two and sew along the raw edge..
Attach a safety pin to one of the shorter edges and push it inside with the help of the pin...
as you reach the other end you can see the right side coming out with the pin at the end..
here it is completely out.remove the pin.
iron the strip to flatten it out and insert a long piece of elastic through one of the open short edges..bring it out at the other end.
tie the two ends to form a circle of a small diameter(about 2 inches will be enough).. .. the idea is to make it smaller than the circumference of a half liter water bottle.this will help hold the bottle in place upright...make the knots twice so that it is strong enough. push the knot inside so that it will not a be hindrance due to bulk while attaching to the edge of the lining later in the bag making procedure.
attach the raw edge of the elastic ring to the side of the interfaced lining with a pin and sew a few times and its done..(see the pic below)
A small tip for you:--We want the bottle to stand upright ..so it should have a support from the bag bottom as well as from the side ring...(you can see how it stands upright on the ring thus made , in my previous post on Vintage inspired bag'..)but for the support from the bag bottom,the bottle should be touching the bottom of the bag..for this purpose, before attaching the ring onto the lining, lay the lining piece flat on a table...Lay the bottle on the lining(perpendicular to the bottom seam of the lining) so that its bottom lies just in line with the bottom seam of the bag...Then mark the position of the ring a little above half way up the side seam of the lining...You may now sew the ring's raw tips onto the lining..Now the bottle will be getting support from the side as well as from the bottom.. Hope my tute makes some sense.. Its the first time I am attempting at one.. If you have any doubt pls don't hesitate to write to me and ask.
With warm regards, Mini