Research, research & more Research!!
Ask as many questions as you can!!
I didn't know about alot of the forums out there when I build my pond. If I did, I would have done things alot differently.
I started out with a 600
gal pond and within 4 months, I was digging my 5000+(and still not large enough) pond.
I added a skimmer, purifalls, bottom drains. And just this past summer, added 4 55gal barrel TT/biofilters plus, another makeshift bottom drain.
If I did my research the first time around, I would have never had sloped sides, id have removed the treestump so I "could" enlarge the pond if I wanted too.
I would have never put the rocks in the bottom of the pond(see photo gallery) as the removal was a Bi**h!! (I did it all myself) 39 YO female here
But all in all, I love my pond.
It's the best therapy in the world!!!!!
Good luck and don't hesitate to ask questions!!
And for your pump~ I'd strongly recommend an out of pond pump!!
Trust me~ been there !!