What onboarding tricks help reduce trial drop-off for technical software?

We used to require complete configuration right when a user signed up, but our drop-off rates were terrible. Watching heatmaps helped us realize people weren't losing interest in the product they just hated doing admin tasks before seeing any real results.

We're trying to restructure things so users see sample data or a working preview first, then finish the heavy integration later.

If your product relies on heavy account setup, how do you hook new users in their very first session?