Any tips of keeping lettuce fresh in the crisper
Section of the refrigerator. Mine starting turn brown
Quickly.

Those freezer bags, with the lettuce cut up, rinsed work best for me, squeeze all air out and I keep in in the crisper for at leat 3 days.

You need to make sure all the water is off the lettuce before you store it so let it drain well air tight containers or bags work just fine, if you find the lettuce discolouring before you have used it then the only thing I can suggest is buying a smaller one.
I also find that lolo roso lasts longer than plain white lettuce.

any tips of keeping lettuce fresh in the crisper
section of the refrigerator. mine starting turn brown
quickly.
Be very picky about what you buy - if you see any browning anywhere, look harder for a head that is cleaner. Usually you'll see some browning around the cut stem. Remove the outside leaves, break out the stem and discard it and store the head in a plastic grocer bag in the crisper.
The browning is due to a common bacteria. So cleanliness counts in your handling of the product.

Please rate if you please

Excellent answers above!