Here's how I do my pants fitting.......
1. Make all the necessary pattern alterations. I compare flat pattern measurements with those of the pattern. As I mentioned before I also compare RTW pants measurement with those of the pattern. I outlined my pattern adjustments here. I also look at the pants leg widths and lengths to make sure they're ok. When I'm satisfied with the results I proceed to cut out the pattern. I have to admit that most of my pattern adjustments are done at the flat pattern stage.
(Pattern being compared with RTW pants that fit well)
2. If I'm working with a new pants pattern I ALWAYS make a muslin. My muslin is either made out of the usual bleached muslin fabric or something or a similar fabric to what I plan to sew. If there are any side pockets then they're taped to the pants piece and they're cut out as a unit with the pants piece. So basically I'm just cutting out 2 front and back pieces. I don't tend to fiddle with other details (back pockets, etc) during the fitting. I will cut out back yoke piece of course because it's important for fitting purpose. I don't even bother cutting out the waistband.
3. Here's how I assemble my pants for a fitting (and actually when I sew them if no fancy top stitching is involved)
-Sew front pant to back pattern at sides. Do the same with the other leg.
-Insert one set of pants legs into the other with right sides facing.
-I sew up the crotch below the fly to leave an opening so I can try on the pants (if there's no fly then I leave front upper pants open about 5" or so). Stop sewing about 1" away from the inseam on both pants front and pick back up sewing 1" after crossing over back pants inseam. I basically leave a gaping hole in where the inseams connect. By leaving this open it just makes it easier for me to do any inseam adjustments. Sometimes I may have to adjust the front or back inseam and with them left unsewn it's easier to do that.
4. I try on the pants with seams out. I pin the front crotch up at the appropriate seam allowance. With the pants inside-out and the seams visible it's easier for me to do the necessary tweaks. This is especially helpful when making crotch adjustments.
(Fitting with seam allowance out for easier tweaking)
5. I place 1" elastic at the waist. At this point I make observations of the pants and begin to do my normal suite of adjustments. I move the pants up or down until I get the crotch depth right. I look to see if any length needs to be added in the back (which is where I sometimes come up short). If the length issue are resolved then I look at the circumference and take in or let out as necessary. I suggest you consult your preferred pants fitting book(s) for helpful advice on the adjustments you need to make for your body type.
6. Once I've noted the changes I go back and correct them on my tissue. I never usually make any drastic changes which is why I just transfer the changes to the tissue. If I made drastic changes I would probably just use my muslin as a pattern instead.
Ok, so there you have it! I told you my methods weren't complex. See, you didn't believe me (wink)! As I mentioned before I do most o of my pants corrections at the flat pattern stage. In my opinion it can be really difficult to tweak pants. For me to start with a pattern that's similar to my measurements and a RTW pants that I have and know fits helps me avoid most of the crazy, unnecessary fitting woes. It's been my experience that when I've got the crotch curve/length/depth in the right ball park all I have to do are minor tweaks--such as deepening back darts, fixing gaposis in the waistband or yoke, etc. Which is why I go to great lengths to make sure my pattern adjustments are done ahead of time & I've compared the pattern with RTW as a backup strategy.
Ok, I don't know if this was that helpful but I hope it helped put some of you people who have been working tirelessly. Trust me I understand the struggle. Everyone does things different so I'm sure you will find what works for you. If anyone has any other pointers they want to share feel free. Never underestimate how your experiences can be helpful to others!!!! In the next post I'll summarize what I've learned about fitting pants (strategies/tips).....