I am a first time investor & would appreciate any tips/ advice from you all.

Appreciate the tips!

They have 2 pet rabbits (the lease allows small pets), they had a bag of rabbit food tipped over and spilled in the cages, and hay outside the rabbit cages in an open bag and also sprawled out on the floor of their kitchen.

Any tips from experts and experienced investors out there?

Search the term “house hack” on the forums and you will get all different opinions, tips and tricks, best practices, etc..

But,they smoke inside (against the lease) and therefore I have said I wouldn't replace doors and windows with them doing that because of additional damage it causes.Other than that, when they didn't pay that would've broken our lease I would've thought.

Any tips to make connections with other people at the event and walk away with numbers?

I know tools such as the BP calculators are available for use, but I want to learn what goes on behind the scenes to fully understand the numbers (math) and specifically what it means so i can better gain an understanding & make better investment decisions when the time comes.Any advice/ tips or tricks on analyzing deals & double checking the numbers (before proceeding with the deal? 

Also, what are some tips and tricks to finding investors?

Fix broken hand railings, don't allow swimming pools or trampolines, etc.