Welcom to the forum. Creel surveys can be very simple. I keep a notebook with me when I fish. I write down the weight and length of every fish I catch and whether I keep it or throw it back. I then compare the weights and lengths to a standard scale for the type of fish caught. Creel surveys or fishing logs are great indicators of how your fish are doing. My fish are about 83% of standard weight which is up from only 79% earlier this year. I would not know that without a creel survey. Below is a link to the standard weight scale I use.
http://www.aces.edu/pubs/docs/A/ANR-1193/I found that keeping records of all the fish caught in my pond has been a great way to evaluate the population. It's also a lot of fun to watch how different management strategies impact the weight of the fish.
