Suggestions on how to find a flatmate in Edinburgh?

I share a flat with a good friend who’s just told me he’s planning to move out in the next month or so. Not sure how best to find someone to take up his share of the rent once he’s flown the coop. I live pretty centrally and pay a good rate, so I can’t imagine it’ll be too hard to find prospective flatmates, but I really have no clue how to go about advertising online/vetting people to whittle down my options. I’m not too good with strangers…