Start with BiggerPockets Ultimate Beginners Guide (free).

Lowes and Home Depot always are running promotions for $75 for whole house labor.

Competence is what ultimately matters.

But, we also bought one house sight unseen that was a ultimately a not so great flip (same team, different area) which we were able to eventually fix (a cost of the fast-moving market, and us missing some quality clues) (Hint: have reserves on hand for a handyman!).

There is no generic winner or loser buy box, just make sure that ultimately what you get aligns with you and your personal goals. 

We had a great realtor and lender if I can be any help with those (and I'm not related to either LOL - so not trying to promote anyone, just offering to help)! 

Can I ask what rate you ultimately decided on and which of those 3 services was closest to that rate?

@Robert Rixer, I don't know how creative these are, as many are common plays:Valet TrashFencing in first floor yardsProviding washer and dryers for added rentReserved, Covered parkingTech PackagesInternet and Cable contracts, with reimbursementsPayment Plan rents, with small service charge (i.e. bill 1/4 rent each week)Reserved Rental cabanas at poolPrivate pool party rental optionGolf Simulator in clubhouse - fee basedOn site, self serve car wash (quarter feeder style)Charged group fitness/personal training servicesGame room in clubhouse with monthly subscription for tenants (Xbox, Playstation, etc)Changing out high maintenance grass for astro turf or lower maintenance/lower water use shrubberyBut ultimately, I think a lot of NOI increases come from deep dive into understanding EVERY expense and finding ways to minimize them, and/or no outsource them.Train maintenance team on basic HVAC and appliance repairs (find way to get them licensed as needed)Buy paint sprayers for faster, easier turns versus having to hire a contract painter, and possibly repaint whole unit each timeStandardize all finishes, so you can buy in bulk, everything from hinges and door knobs to cabinets, paint colors, and light fixtures.Potentially get leasing people onto lower base salary with higher bonus potentialBulk/bundled insurance across portfolio (even better at scale is to self insure)Regularly test sprinkler systems for leaks.Non-NOI, but benefit to you: partner with insurance agency to get referral kickbacks from your tenant base for renter insurance.  

His post high school plans the last couple of years was to get his real estate agent license, with the ultimate goal of investing.

Ultimately, consider your long-term goals and financial stability when making your decision.