Quick Reply: Most RTO disputes turn on a document that is missing from the file rather than on the decision itself — get the file first.
Direct answer. Vehicle paperwork splits into getting a document (licence, RC, permit), moving one (transfer, NOC, address change), and disputing something (a challan, a suspension, a rejected application). The third needs the record behind the decision, which is what the RTI guides here are for.
If a department has the record you need and will not hand it over, an RTI application is the route that forces the question. Start with the RTI application format, and if the reply does not come or does not answer, the first appeal is the next step.