Welcome, @Joshua Jones!
Congrats at getting in on the Union City frenzy early on. Sounds like your spot is in a great location.
Focus is key, but you can only focus once you know what you're after.
If you're seeking to maximize cashflow, you'll be targeting different areas than if you're seeking long-term appreciation, which can be a risky proposition depending on the location and current cashflow.
For example, on paper, returns in riskier markets will appear higher from a cashflow standpoint (think rougher sections of Newark, East Orange, etc.). However, those investments will carry more risk and are [generally] more management intensive. Not always recommended for rookies.
On the flip side, investing in more desirable areas of Hudson County may lack the cashflow that other markets can provide, but for a variety of reasons, you may feel safer investing there. You may forecast greater appreciation; you may prefer the proximity to the city; you may prefer that tenant base; or, you may prefer to invest closer to where you live.
Happy to discuss further, and best of luck!