My first 'big' tank was a 110 tall purchased on August 25, 2013 and with the learning curve, equipment acquisition and upgrades, I started to cycle it on November 16, then added my first fish on Dec 7.
My biggest hurdle was self confidence. It was all new to me and sounded like a lot of pieces had to fit together perfectly to keep these animals alive.
Thanks to RC, I learned a little at a time. By the time fish went in, I was fairly certain that I would be successful, but also prepared to make newbie mistakes.
The biggest hurdle of the build itself was plumbing. PVC glue, physics of flow and poor equipment choices made that a definite head scratcher.
My current 350 build started on August 1, 5, 2015 and is taking about the same. Even though it is much larger, experience helps. I had to do some demolition and room prep, buy lots more equipment, and completely buff out the acrylic. Still, I got the cycle started on November 8, 2015.
Don't rush, and savor the entire process. The reward for all your hard work and patience will be a beautiful piece of the ocean that will provide hours of enjoyment, plus the pride of having created it yourself.
And best of all RC is here to help!