One very important thing to think about that I haven't seen mentioned is having
a ground fault protector so that you don't get shocked. I almost killed myself
when I put my first pond in.
I think that the preformed ponds for first timers are very easy.
I also really like the frog water spitters.
I do not like the preformed waterfalls though.
I agree with the mention of seating around the pond. I have 2 ponds and the one
that's raised with a bench seat around it gets way more attention and the fish
eat out of my hands. The other pond that is not raised does not get as much
attention and the fish are not as friendly.
Hope this helps.