Many people think that Hahn is located in the suburbs of Frankfurt. It's not! You may better call it Trier Hahn, because it is half an hour from Trier and 90 minutes from Frankfurt. It would be even closer to call it Luxemburg Hahn, because Luxemburg is located 60 minutes from Hahn!
Unique Suggestions: Don't take a taxi, but take the bus to get to Frankfurt. It leaves frequently and is about 12-15 Euro and leaves for Frankfurt main station.
Fun Alternatives: It's much better to go to Frankfurt Airport. It is only 15 minutes from the city centre. Calculate exactly to see whether you may have cost advantages.