In the greater Boston area alone, there are more than 50 accelerators, incubators, and support programs that offer startups co-working space, education, capital, mentorship, networking, and other support. With so many options—and so many differences between them—how should a founder decide which accelerator to apply to? And, more importantly, what can be done in the program to ensure growth actually is accelerated at the end? We talked with four experienced accelerator alumni to find out.