My help guide is based on the following assumptions that the small sailboats you are looking at are 17 feet under and have been sailed in fresh water only.  While these are my assumptions, some of the information mentioned may be applicable to larger size sailboats, and those that have been sailed in salt water.

It is just good common sense to inspect any boat, including small sailboats before you buy.  If you are not familiar with sailboats, then contact a local sailing club and you may find there is an experienced member that is willing to assist you.

Some common things you should look for would be soft spots in the deck and hull.  Do not be afraid to climb under the boat and look for cracks or patches in the bottom of the hull.  Keep in mind that some hulls have been patched and then painted over so look inside and outside the boat.   If there has been a repair to the hull ask questions to find out if it has been done properly. Check the transom and make sure its solid.  Look for cracks and do not be afraid to place your hands on the transom and give it a tug and check for movement.

Find out if  the sailboat has the original mast.  If the mast has been replaced.  If it has, find out if the original sails that came with the sailboat fit it or if the size of the sail or sails have changed. This is very important because it can affect the performance of the boat, and your ability to easily find the proper replacement sail if needed.  Check the mast and boom for cracks as well.  Make sure all the rigging is there.  If  you are not sure, then ask the person who is selling the boat to explain how everything goes together.  Find out age of the lines and rest of the rigging.  Check and inspect the pulleys for rotation, cracks, and weathering.  These may be parts you end up having to replace and it will be helpful for you to know.

Ask when the sailboat was last used and how often it was used.  Where was it used.  For the purposes of my help guide I have made the assumption that the small sailboat you are considering was sailed only in fresh water.

 Take notice of the condition of the sailboat when you first arrive. Was the sailboat covered or tarped? If you have traveled a good distance to inspect the boat, then inspect it, and then go get a burger, and ask the owner if you can come back in an hour or two and inspect it again just to make sure you did not miss anything.  If the owner wants to sell his or her boat and has nothing to hide, then they should not object to this. Keep in mind that any major damage you miss can be costly to you.  Keep in mind that you will be paying someone else unless you have the skills to repair fiberglass, paint the bottom of a boat, and replace worn out or broken hardware.  This is why a good inspection is worth its weight in gold.  It also helps you bid properly in an auction.

Ask to look at the sails.  Feel them with your hands and notice if there is a slight stiffness or crinkle to them. Pay attention to the stitching.  Look for patches or sail repairs that might have been done with sail repair tape.  If you are not sure about something then ask the seller.   Although a sail might be somewhat discolored, that does not mean its a bad sail.  Sails, esp white, do get discolored over time.  There is a proper method for cleaning them, and its not the washing machine.

If the sailboat comes with a trailer, then ask if the lights work, inspect the tires, and ask the age of the tires and when the last time the wheel bearings were greased.  Trust me you do not want to end up stuck on the side of the road with your new used sailboat because the bearings seized up in the wheel or you have tire issues.

Very Important!!!   Ask if the boat has a clear title.   If there is no title do not buy  the boat.
Ask if the trailer has a clear title.   If there is no title ask your state Department of Motor Vehicles what is required for you to license the trailer.

Get any and all freebees that you can.  If a seller is willing to throw in an extra set of sails, paddles, oars, lifejackets, or any thing else is somewhat decent condition, take it.  You can always resell it on ebay if you do not want to keep it or cannot use it.

Hopefully you will find this guide some what helpful.  Keep in mind its only a a guide and even experienced people sometimes overlook things when they are excited about a purchase.

Jason