(I don't mention it all the time, but, as a general rule: press everything as you go along!)
Step 1: Find a Good Pattern
Measure yourself accurately & choose the correct pattern size.
Step 2: Pockets I
Sew pocket facings (right side up) to pocket linings (right side up).
Step 3: Pockets II
Understitch the lining.
Press to right side.
Top stitch the fold.
Step 4: Pockets III
Sew up the lining & zig zag the rough edge.
Step 5: Sew Up the Crotch Seam
Step 6: Zip Fly I
Turn & press.
Pin & sew onto the Front of your Left-Front pattern piece.
Press & turn to the inside.
Step 7: (* Cutting Down Zip-Strip...)
Snip a bit of the teeth off from where you made the cut.
Open a bit of the end of the zipper, slide on one side & pull it down a little.
Jimmy the other side in & hold on to the tapes you created as you pull the zipper down.
Trim off the excess at both ends.
(Before the zipper is fully attached and sealed in, be VERY careful not to pull the zip head off the end of the zipper - as I have done, many times!)
Step 8: Zip Fly II
Pin & tack the zip (facing out, closed with pull at top!) with the teeth just poking out.
Prepare the zip shield. Sew up 3 sides, turn & press.
Pin & tack over your original tacking (& remove 1st tacking - I use 2 colour threads to make it clearer).
Sew down and remove the tacking stitches.
Step 9: Zip Fly III
Turn your shorts right side up. Close the fly so there is no puckering. (Pic 1)
Pin the zip to the left side of the fly. Turn to wrong side and pin JUST the zip and left fly facing together. Tack this down before sewing. (Pic 2)
Sew up the bottom of the zip shield and the left fly facing. Through the bottom of the zip. (Pic 3&4)
Pin the zip shield out of the way and sew your left fly facing down with a top stitch curving to the base of the fly. (Pic 5&6)
Step 10: Sew Up the Side Seams
Space the pins evenly and remove as you go to avoid 'bolting'!
Step 11: Belt Loops & Waistband
Pin belt loops onto right side of trouser waistline.
(1" from pocket. 2" from side seam. 1" from centre back edge. Both sides.)
Attach medium weight iron on interfacing to wrong sides of waist band.
Pin & sew 1 side of each waistband (right sides together) to the waist.
Turn the waistband right side up. Slacken the belt loops & pin on the back of the waistband, right sides facing.
Sew in line with the zip openings at the front, then along the length of each side of waistband.
Step 12: Centre Back Seam
Sew together twice a few mm apart for extra strength.
Zig zag the raw edges and press open.
(I like to press to one side and top stitch down for even more strength to this seam)
Step 13: Finish the Waistband
Step 14: Sew Up the Inseam
Sew from the crotch down to one hem, then the other (crotch to hem again, crossing over at the crotch to strengthen).
Finish the raw edges with zig zag, then press open.
Turn up the hems at the bottom. Either:
Double hem & 2nd top stitch
Finally, give them a really good press with lots of steam and your shorts are ready!