In order to wear a corset properly, there are many steps you need to take. First, you need to make sure that it fits correctly. You can view more information about sizing here.
Once you are sure your corset fits correctly, you need to make sure that it is laced up and tightened the right way. First, make sure that all the snaps, buttons, or lacing are unfastened or loosened, especially around your bust and the widest part of your waist. Put the corset on and fasten the front snaps or laces.
Next, to lace up your corset, you will most likely need someone to help you make sure it is the correct fit, since you cannot reach all the grommets to ensure even lacing. The lacing should be the tightest at your natural waist, or the smallest part of your middle. This is usually where your ribcage ends and your waist and hips begin to widen (it is also right about where your belly button is). Because the lacing is tightest here, you should also finish lacing your corset here and tie the bow at this point.
Use a simple bow to fasten the lacing closed. Once a lace corset is correctly tied up, you may cut any long lengths of lacing that may be too long and are a distraction. Once the corset is initially laced according to your own body, it will be easier to lace it up on your own next time. However, some most intricate corsets can always require a helping hand, or at least a mirror to make sure the lacing is even.
You may be able to keep the lacing tied and still get in and out of your corset using the front snaps only. This may work for some corsets, but it is not recommended, as it is not ensuring the best fit every time your wear it. Weight and body shape fluctuations make it necessary to re-tighten your corset every time you use it.
The corset should fit snugly, but not be uncomfortable in any way. If you are wearing high stockings or additional undergarments, put these on first. It will be easier to bend over.