You get Empire Points by posting, advertising in the chat boards for the Guild(you have to tell me to go look at your advertising, I won't just give away points like they fall off trees or something O_o), donating(NP or items, or both) and being helpful with new members, and well, in general, being active is what will give you points. Remember that being active doesn't mean you have to post like crazy, you can be an active member just by donating :)
*Using your Empire Points
Using your Empire Points is quite easy :), just go to Chibinekomatt's Shop, and look for the items prizes 100.000+. For example, if you have 10 points, you could exchange it for an item prized 100.010, the last numbers indicate the points you need to get that item. Just neomail me with the item you're requesting and I'll discount it from your points, and send you the item :).