Hi @Xiao Xiao , for any area that you're evaluating for the first time, I'd do a few things:
1.) Drive around at all different times of day & night. Visit local businesses and ask owners/employees questions about the area. It sounds like you've already been doing this so kudos to you!
2.) Talk to property managers in the area. Tell them that you're evaluating the area and, if their guidance on local blocks is accurate/honest, you'll consider them to manage your property. PM's make their money serving other investors in the area and are intimately aware of the quality of tenants in their area.
3.) Go to REIAs/meetup groups in the city/Essex County. There are a couple meetups that come to mind which are very good in the area. Talk to other investors who are active locally and get their feedback on the neighborhoods you're looking at.
4.) Lastly and possibly most importantly, find a quality real estate agent who will guide you as to crime, transportation, schools, tenant quality, job growth, etc. in the area. These people are your eyes and ears in the market and when you find a quality one, they're worth their weight in gold (or bitcoin lol).
These are just the steps that I use to get more familiar w/ certain areas. This is NOT an exhaustive list and you may see many other interesting ways of identifying target areas out there (e.g. the Starbucks or Whole Foods indicator) so stay curious and keep learning!