How to not suck as THF in the Dunes.
Step 1: Don't use a dagger.
Step 2: ???
Step 3: Profit!
Seriously though, if you want to level THF in the dunes, I recommend leveling MNK to 10 (if you haven't done so already) and then taking the Hand-to-hand skills you got on MNK on THF to get a head start on being an awesome H2H THf doing 300+ combos in the dunes u wot m8?! (Also THF/MNK works because of martial arts Job trait. :<) Using a RA of choice between melee swings helps with DPS and TP gain.
THF doesn't necessarily suck... it's usually 95% of people who play it because they ironically level it to gain gil... right? :<
-Shrek