I, admittedly, am not an awesome cook. That's why I love super easy recipes. But I have learned a few things over the last 15 years. (Thank goodness!) Believe it or not, I didn't use to use a different measuring cup for solids and liquids. Um... that makes a HUGE difference. Oh.my.gosh. I don't know how I made it all the way thru high school and into marriage without realizing those measurements are different.
Another thing I have learned is to always make sure your ingredients are fresh. This makes a huge difference!! If you are making cookies using the same flour you bought last year, that has been opened all that time... they aren't going to turn out as great as they would had you used fresh flour. Spices are like this too. I bought a spice rack at a garage sale years and years ago and never thought to replace all the spices. No wonder when I used spices you never could tell. They were old and... yuck. Penderys.com is a great site to purchase fresh spices, such as sweet paprika. It's a great overall site with lots of great tips about spices and cooking.
What have you learned thru out the years?
Disclosure: I received compensation for the link in this post. The other thoughts are totally mine. :)