I'm a Boston-based angel investor, member of Boston Harbor Angels and Walnut Ventures, as well as on the advisory board at The Capital Network (TCN). In my own investing (about 2/3 with groups, 1/3 on my own) I prefer seed stage, the groups tend to come in a little later.
There are many angels who are not affiliated with specific groups. These range from very well known folks who are in many deals around town, to high net worth individuals who might invest in one or two deals in their own areas of expertise. These latter ones are particularly hard to find, so networking is the key skill.
I'm happy to chat with you about the local landscape, but I also recommend TCNs educational programs dealing with raising capital. They have mentors and advisors providing the content as well as being available for networking.