For seinen, I'm currently crazy on Urishibara Yuki's Mushishi. Each chap features the place Ginko is in and the mushi causing trouble there. It's a beautiful, slice-of-lifeish fantasy series--definitely for seasoned manga readers. Try the first volume. Hope someone picks up scanlating this again soon.
You might also want to try the urbanny What a Wonderful World by Asano Inio. If I remember the chaps well, I liked stories 2 and 3 especially.
For shoujo, I highly recommend Miura Noriko's Kirai. It isn't exactly slice-of-life in terms of genre but it gives a similar feel. The drawings might turn you off at first but the fresh approach to shoujo romance (especially if you're not into mush) really glued me despite the bad scans. Again, try the first volume. Hope dragonvoice skips rescanlating chapter 2 and heads off straight to chapter 13.
Let me know if any of these turned out to your liking. Enjoy!
PS: One Pound Gospel by the same mangaka of Ranma 1/2 isn't slice-of-life as well but gives the same feel as any series by Mitsuru Adachi.
But once you conquer the world, then comes the hard part.
What kind of world would you create?