I manage about 200,000 sf of retail and office space in NC and SC. Over the past several months especially, I have noticed a slow down in tenant prospects and instability in long term tenant stability. Several tenants are considering moving to less expensive properties as their leases are up for renewal. Although this will happen irregardles of the national economy, it is becoming more prevelant in our properties. The market I primarily work in (Fayetteville, NC) hasn't quite felt the slowdown because of the growth of the military base.
I use Loopnet, Costar, Catylist, MLS, etc to advertise properties for lease, but have not had very many leases signed from these. I've found that on-site signage and relationships with prospective tenants/retailers is the best way to get the spaces leased. Regarding retail, become a member of the ICSC and go to the trade shows so you can meet the retail company reps that select their sites. This way you know how to talk to (and eventually they will know you) and you know what type of property they are looking for.