By using a data-driven approach to all our property selection, staging, and pricing and occupancy metrics, along with an interview process with the owners, we have developed a great system for aligning with the right owners.

and have been focused on developing my real estate knowledge to grow and expand my portfolio.

Buy a small piece of land (1-3 acres) n a mid-sized WC city for $100-250k and develop a small 2-6 unit multifamily structure (would have to take out an additional construction loan) 5.

Also, you can perfect your technique with minor tweaks here and there by doing one unit at a time.

Should I keep it and wait 5-10+ years until it makes more financial sense to develop the lot?

There are a ton of permutations on that theme and techniques, but that is the core. 

We're looking for offmarket storage & industrial deals and have developed a database of owners and properties, whom we will be calling and visiting. 

The brokerage I am with has their own already but my goal to develop my own brand and would like to have a website that reflects that mission.

I haven't yet read it myself but have heard that it's got a ton of great information and should help you develop a good concept on what to expect in the process, including aspects like closing costs etc.

It seems a recurring theme that networking is key to finding deals outside the MLS among those listed by @Ronald Allen Barney I've heard RE bloggers, those with website bios, those participating in forums such as this, and in person discussions as being ways in which people get to know you and begin to develop a sense of who you are, so later they may think of you when something comes across their desk.