If you are filling your son's developmental needs[0] well enough and consistently enough, he will turn out just fine. Parenting isn't rocket science, specific behaviors have specific results and we actually know a lot about "what are the right behaviors?"

By the way, at 2 1/2 years old, any "bad parenting" that your son received can still be corrected by adjusting your behavior accordingly. Insecure attachment is simply caused by the child not trusting the caregiver enough, so none of it is "set in stone", trust can always be earned through consistency.

In addition to reading the linked article below (highly recommended), maybe you could also sign up to take an attachment test with your child? Not sure exactly how this works, but it would give you honest feedback.

You can also look through this guide on "how to raise nurtured children"[1] and see if anything interests you.

[0]: http://sfhelp.org/parent/d_needs.htm

[1]: http://sfhelp.org/parent/guide6.htm