The two biggest ones that come to mind are the lead laws and the tenant payment laws.MA is making a huge push to be lead safe/free (don't quote me on the technicality of the terms).

I would advise also that you don't reach out to the biggest investor-friendly Agents in the area -- 90% of the time, they already have their clients and new clients tend to be friends of existing clients. 

Aside from providing the basics (ie. listing tool to get the property published to 10+ major sites, scheduling tool to schedule viewings, tenant screening with comprehensive applications -- pulled reports from TransUnion, which include nationwide criminal background checks + credit checks + eviction history, digital lease creation tool, rent collection tool, and maintenance tracking tool), some services also offer your tenants additional capabilities which makes it an easier sell on your end when getting them to transition over (ie. their ability to report on-time rent payments to the credit bureaus; this can create an added incentive for making sure they pay that rent on time).

I won't say I lose sleep over them, but there have been some homes and commercial buildings made from containers, that I absolutely love the design of.My very, very limited knowledge is that there isn't much financial incentive to them. 

So the biggest bang for your buck is 5% down bracket since putting 10% down only gives you .25 less fee.Just make sure your lender walks you through the nuts and bolts of how to use VA strategically and the pros and cons of each stage. 

I think too many wholesalers are focused on building the biggest buyer's list without vetting each of them.

Honestly the biggest issues are when the wifi goes out, and you tried to update the lock with a new code, but it didn't take because the wifi is out. 

Biggest piece of advice: don't be afraid to file an extension. 

My biggest enemy in my pursuit was my self, I didn't really know what i didn't know in the beginning but perhaps more importantly i was not nearly as confident as i should have been with what i did know.  

Know the red flags before you hand over too much money this is the biggest problem finding good trustworthy people and also knowing when to let a bad contractor or agent go.