The first place to look is always the Internet. Try to find meet up Goth groups or Goth events in your area.
Step2
Wear your Goth wardrobe in any and every situation you can possibly get away with it. We have to go to work, and work doesn't always appreciate that sort of thing, but hey, you have some free time, right? The right clothing is like plumage, it attracts those you want to attract, and repels pretty much everybody else. You should find at least one Goth if you practice this long enough.
Step3
Visit Goth-type sections of bookstores. Poetry seems to be popular, as does some kinds of gaming. Finding your local gaming store can also work, the staff generally knows the Goths by now. Also try Goth sections of music stores.
Step4
Look for subtle tells as to people's inclinations. Goths are findable working for Burger King, if you know how to look for the telltale black nail polish and slightly extreme eyeliner. Looking for band albums is also a good tell, if someone has Voltaire, Cruxshadows, and Seraphim Shock in their car, it's a good bet that they're a Goth.
Step5
When you find your prospective Goth, don't be shy about introducing yourself. Don't do anything foolish, like immediately go to a private house, but be friendly and invite your Goth to coffee, or ask about what public place Goths can be found in greater number.
Step6
If all of the above doesn't work, find a local homeless shelter in need of help, and organize a Goth community drive to help them. Scheduling this around Halloween is good, but any occasion is better than none. I mean, just because we're Goth doesn't mean we're not into helping people. We just insist on wearing black while we do it. Put out flyers, tell people about it, and you're sure to attract the kind of Goth you actually want to meet.
Tips & Warnings
Be constantly on the lookout for small signs of Gothdom. Most Goths don't advertise twenty-four/seven, since most of us have to get along in the real world, but we'll always have some kind of tip off.
Keep your own tip off on you. It could be as simple as a piece of jewelry, or a hat. Full on Goth clothing is a neon statement of your intent, but one piece of Goth clothing is a charming wardrobe accent.
Never, ever, ever go to a private place with someone you have just met. Ever. The first you go to someone's home, do not go alone. Make sure that a good friend or family member knows where you are and when you should be home.
Never invite someone you just met to your home, especially if you live alone.
Do not think that your local Goths will be into the same things your old group was. Goths are highly individual creatures, except when we're not. Be polite, and keep your strong opinions to yourself until you know how they will be recieved. Live your beliefs, don't preach them.