does anyone know where i can get some ideas to design my aquarium??

If you do a go0gle image search and type in "fish tanks" you'll get a lot of neat pics. Or type in different types of things, goldfish tanks, tropical tanks. Whatever you can think of. You'll find some neat pictures.

Design as in custom building a filtration system?

you could also try looking around here on kokos, at pix of other members tanks thats werhe i get some of my inspirations

Do a go0gle search on "aquascaping an aquarium".
Some people are just so talented...*sigh*...although my tanks look pretty good(if I do say so myself) considering I can't have live plants. Good luck.