I have a couple of rental properties. The tax considerations are a little complex. Make sure you keep very good track of every penny you put into the place to get it ready for renters and once you have renters keep track of repairs you make. It's not necessarily tax deductible but it is considered an expense so you can play that off of the profits you make so you don't have to pay as much income tax.
Unless you are pretty handy and have a decent lawyer on tap, you may want to hire a property management company to handle stuff for you. They will locate and screen potential renters, help you determine a fair price for the place, deal with the renters as far as requested repairs are concerned, inspect the property to make sure it is being maintained, collect rent and any deposits required, compose the lease, and hire a lawyer if the terms of the lease are not being met by the renter. They usually take around 8%.
Generally you need to notify your mortgage company if you choose to rent out a property. Some mortgage agreements do not allow for this so you should probably find out first. You also need to let your insurance company know so they can adjust your home owners accordingly. You won't need to insure the contents as heavily anymore (just structural stuff) and have some liability insurance (depending upon the state and type of property). You want to make sure you are covered if someone injures themselves on your property. You will also need to notify the state or county if you pay property taxes as these are generally calculated differently if you rent vs it being a primary residence. This is not a step you want to skip and hope they don't notice because, trust me, they will figure it out.
We already had an annual contract to service our HVAC anyway so we just keep that up. It's not expensive. As for the appliances, I figure that's what insurance and security deposit are for. I haven't found that these things get older faster and need to be replaced faster because there are renters. If anything breaks the management co lets me know, gets an estimate for repairs, and then either just goes ahead with it (if it's less than a certain predetermined amount) or asks us if I want to repair or replace.