This is how I was taught to do measurements in my high school home economics class....uhumm,,... 20+ years ago.
I think it still applies.
You are essentially trying to find the "largest" place to measure.
I also carry most of my weight in waist.
I find that it helps if I just wear my bra and panties and stand in front of a full length (or mostly full length) mirror to see if I'm putting the measuring tape all around myself in the right place.
For the Waist:
Place the measuring tape around the waist area (above the belly button) going around the largest part.
For the Hips:
Place the tape around lower abdominal area making sure the tape goes around the largest part of your butt.
For the Chest:
Same thing -- take the tape around the largest area.
Some other good measurements to follow is the Thigh and Forearm and Calf.
The important thing is to be consistent with how and where on your body that you measure. After you do it a few times, you get used to "where" you measure.
Again, I think it helps if you do this in front of a mirror.
Hope this helps.