Best Ways to Accurately Predict Rent & Property Tax?

[Kyle Posey]

I'm an out-of-state investor, still narrowing it down to a couple markets, and I'm finding it quite difficult to predict a rental rate when comps on zillow/realtor vary by ~$1000/mo.  

ANd then I'm also trying to understand property taxes better.  When looking at individual property on the county tax website - it's showing a property value of less than half of what it's selling for.  ANd of course, I'm trying to find out if my purchase would bring the house value up to what I paid (which would turn a $1500/yr property tax to nearly $3500/yr if taxed at the same rate).

Any wisdom on these areas?  I don't want to be ignorant when going into a deal and having my cashflow eaten alive by increased property taxes or inacurate rent predictions.\

Thanks!