I currently own 4 (soon to be 5) SFH in my actual neighborhood.
I have a few tips for the various aspects of being a property investor, landlord, an operationally.
I like homes close to mine. It makes it easy to maintain them and keep an eye on things. I tell all prospective tenants that I am their neighbor and that alone helps filter out the ones that are thinking of hiding things (pets, extra roommates, etc...)
I buy homes with good bones and plan for the big stuff. I am slowly doing metal roofs as needed. I do the majority of work myself and I try to do as much as budget will allow before getting a first tenant. All properties must be at least $300 cash positive per month for them to be of interest for me. All of that profit goes 100% back into the properties for fixing and improving. I am playing the long game. Once I have 10 homes paid off then I will likely quit my day job and leverage those to buy more to grow the snowball.
When doing initial fix ups, plan for low maintenance and hassle in the future. Install hardwood, not carpet. New quality appliances bring in and keep better tenants. If you see a potential problem when looking to buy a place, it WILL be a problem at somepoint in the future. Quick example > bought a house last year with a remodeled shower but a shitty thin shower pan. I knew it would be an issue and sure enough it cracked. I now have to limp it along with ugly epoxy till current tenant takes a 1 week vacation and then I have to hustle to fix it correctly and for good. Just do it while the unit is empty and remove your future headache. I did not take my own advice because I bought 2 homes last year and needed to get to work on the second... Lesson learned.
Operational aspects are my least favorite thing. I have learned to enjoy them more by developing a good system for finding and screening tenants.
This came all from the help of a Pinsider a few years ago and has been a big help. I have learned to be hard and strict with my filtering of tenants to find good ones. You will have a bad one get through at some point, but refining this has meant way fewer headaches. Main things are 3x rent as total income, all persons must be listed on lease (no, cousins that showed up or extra dogs), no smokers period!, set clear expectations and verify by checking in. It is always a good idea to do a post move in inspection to see how the tenants live. Then go in 6 months later to "check" on the house. You want to give a good tenant their privacy but also see potential issues before they get worse.
For me personally, I will be in 'pay off the loan' mode before I get any more homes. Mainly becuase maintaining 5 seems to be my limit.
My current goals are to turn 2 year tenants into 5 year tenants. Turnovers take time, energy, and cost money. Despoite what someone else said, I NEVER raise rent ever for a good tenant. If they pay on time, take care of the property, and notify me ASAP when a problem comes up; then rent stays the same for as long as they love there. My properties are all cash positive so I have no issue making a little less each year (taxes and operating costs/ins go up) if it keeps a tenant in the home for multiple more years.
With a 15 year mortgage, I would like to only have a max of 5 tenants in that time frame.