Have it come from actual grassroots, have the focus and funding not go to the presidency but instead on lower levels of Government, have Perot actually put an ideology behind it that the other parties weren't offering at the time instead of letting it become a grab bag of Democratic and Republican rejects, and crucially have it not be Perot's vanity project. Maybe then it could maybe sustain itself as a relevant third party for more than one election, but at that point it's not Reform anymore- and even then, you simply won't get a 'American equivalent of the Liberal Democrats', because unless they can displace the Republicans they'll go the way of the Populists.