OK I will give this a try on Melissa's golden rules. Remember I am a crazy boat driver and kids don't try this that a home.
1. Boom should be parallel to the top batten or panel on mainsail.
2. Telltales. Pull the sheet IN on the INside telltale. (Low pressure side of sail) or Let OUT the sheet on the OUT-side telltale.
3. When beating into the wind, both jib and main should look alike in shape
4. Big wind boats on a diet, little sail shape everything tight, Little wind have to eat more, big sail shape everything loose goose. This has to do with the draft or belly of the sail.
5. Fly the mainsail first than the jib. This has to do with trimming order.
6. Big wind, reef main first than the jib to trim out weather helm. Unless you are flying a 130 or greater jib than reef jib to 100-110 percent first.
7. Jib tracks cars.. If you beating move back,, if you are running fast have to move forward. Fine tuning - Move LOWER (back) to fly LOWER telltale, mover HIGHER to fly the HIGH telltale.
8. Boom and backstay controls the upper 1/3 of the mainsail, traveler, downhaul, cunningham along with vang controls the lower 2/3 draft of the mainsail.
Don Guillette probably has the best sail trim book out there. Master his book and you will know more about sail trim than 90% of the people out there. The book is easy to read plus comes with some handy plastic guides to take into the cockpit to help learn how to trim your boat.
At exactly 10 sec into this video you will see that the 1st reefing lines are not slack and its causing the sail to be out of shape. Make sure all your reefing lines have enough slack in them so they do NOT effect the sail shape. If they are as far out as they can go then you are 1. using to much line to ty them to the boom or 2. they need to be replaced with longer lines.