Normally, if the defendant lacks the means to pay a judgment, you will look to the insurance company to pay. Even if the defendant lacks insurance, you may find that your own insurance covers your losses (if you carry uninsured motorist insurance, for example).
If no insurance policy applies, you could consider suing the other party’s employer if he or she injured you while on-duty. Another option would be to sue the manufacturer or distributor of a product that injured you. The worst-case scenario would be to sue an indigent defendant, obtain a judgment, and wait for his or her financial situation to improve so that you can collect on the judgment later.