Of course the easiest way to get your measurements is to get a friend to do it for you- but if you don't have any friends or just want to do it yourself then this is how you do it.
Basically get a tape measure or a long strip of ribbon marking every quarter, half and inch. Make sure its numbered clearly.
Find the area you wish to measure and simply wrap the tape measure around it. Take notice where the zero starts and match it up to the rest of the tape. Be sure not to pull it too tightly otherwise it may cause a false reading which may mess up the finished product.
Ill add a video later.
There are three separate guides for clothing commissions. Upper body, Lower body, and corset. Not every measurement will be needed depending on what you want. Honestly its best to find them all and let me decide which you need but if you have questions about a specific style or are just feeling too lazy to finish all the measurements comment or post in the forums and check back in a few days.
And yes, I do know that all the bases are female. Measuring a male is the same- except instead of bust it would be called chest.
Here are the guides:
Upper body:
Lower body:
Corset:
base is moded from Lovely-whimsy