Play it like you would play DA fox... Get Sixth Sense, Stone Strike, Shuriken Master and Lucky Seven from 1st job skills (for Lucky Seven you need lvl 1 Armor Destructor which requires lvl 10 Stone Strike. Leave Armor Destructor lvl 1 though.). Then survive 'til 3rd job (when you of course go hybrid, taking fox's skills) and then you'll get Precise Pitch, Aura of Luck, Landmine, Chain of Knives, Fan of Knives...
Also, if you want some skills that help you with drilling, you can get Basic Detection (1st job) but that will stop being useful when you drill in deep places. Item Detector (3rd job for lion) doesn't have depth problems as long as you have enough DA (which you'll have as pure DA) but it has long cooltime and tends to fail quite a lot. Oh, and of course Invincible Drill if you don't like to be interrupted while you drill in maps with aggressive monsters.
For build, 2143 or 1144 are the common and good choices. First has a bit more AC (Stone Strike misses a lot if you don't have AC, good to have in some equips), second giving a bit more defence and HP. It's up to you.
Xandrielle ~ Primadonna 18x
Merfialna ~ Soul Master 16x
Elycia ~ Thief Master 13x
HikaruMinato ~ Duke 14x
Nyreem ~ Boxer 11x
DarAnovel ~ Magician 7x
Jewelia/Pearl~
