Here are some sewing tips to help you.
First of all, purchase a zipper longer than you actually need to avoid stitching near the bulk of the pull tab. You can use any of your longer zippers in your stash, too.
Preshrink the zipper. This helps prevent buckling later if the tape does shrink.
Interface the garment zipper seam allowances with a lightweight fusible knit interfacing. Cut 2 strips of fusible knit interfacing about 1' wide on the straight of grain and fuse to the wrong side of the garment zipper area seam allowances.
Stitch your garment seam from the bottom to the mark where the bottom of the zipper will be.
Stop and drop the feed dog on your sewing machine and stitch up and down in the same place a few stitches to sink a knot. Don't backstitch. You can never backstitch straight and this causes bulk in the seam and never lays well.
Raise the feed dog and set your sewing machine stitch to a large baste stitch.
Continue stitching the seam to the top. Do not backstitch or make a knot. Leave a long tail of thread so it will be easy to remove.
Clip the first baste stitch beyond the knot for easy removal later.
Sandwich press the stitched seam. Press open the seam on the wrong side. Then press again on the right side. Use a press cloth to protect your fabric if necessary.
Extra tip: Brown paper super market bags make good press cloths. Avoid the printed area.
Now, wind a bobbin with 'Fusible Thread' and put it in your sewing machine.
Set your sewing machine stitch length to a large basting stitch.
With the zipper face down at the sewing machine, use your regular presser foot and sew from the bottom of the zipper tape to the top on both sides of the zipper. The edge of the presser foot will be along the zipper teeth on the wrong side of the zipper.
The 'Fusible Thread' basting will show up on the right side of the zipper tape.
Place your garment with the zipper seam allowance side up on your pressing board.
With the zipper face down, place the bottom metal stop of the zipper at the bottom of the zipper opening and roll the teeth down along the stitching line up to the top. Press both sides of the tape fusing the tape to the seam allowances.
Note: If you don't have 'Fusible Thread', try using a double sided transparent basting tape or a strip of fusible that you press and adhere to the zipper tape. Then 'glue or fuse' the zipper to the seam allowances.
Now the zipper is temporarily held in place.
Cut a strip of 1/2 inch wide paper medical tape or scotch tape the length of the zipper opening.
Draw a fine line exactly down the center of the tape. There should be 1/4 inch on either side of the line.
On the right side of the garment, place this tape over the zipper seam line matching up the drawn line on the tape with the stitching line on the seam.
Set your sewing machine for top stitching. Put a zipper foot on the machine.
Starting at the bottom of the zipper below the metal stop, stitch across the bottom, stop, pivot and continue stitching up to the top of the zipper using the edge of the tape as your guide to stitch straight.
Reverse your zipper foot and stitch the other side across the bottom and up from the bottom to the top the same.
Now, your zipper is installed. Remove the paper medical tape from the right side. Pull the basting thread out from the top. It should come out easily since you already clipped the thread next to the knot.