Ok well first thing is identify why you can't tank them?
I assume you are shield tanking and not armour tanking the Drake, because if not this is why.... so 2 questions.
Are you becoming cap unstable, and so can no longer run your active shield tank?
Or is it just you need to warp away and let your shields recharge?
if it's question one you need to work on energy management skills.
If Question 2, then shield management skills.
Energy management skills:
Energy Management
Energy Systems Operation
Energy Emissions Systems
and anything that will improve cap useage such as warp drive operation.
Shield management:
Shield Operation
Shield Management
Shield Upgrades
Tatical Shield Manipulation
Shield compensation.
And less so but also specific shield damage type compensations.
These are from memory as I'm at work!
These skills will strengthen your ability to absorb DPS for your current fitting, but will also allow you to fit more higher ranked modules as well.
If you are trying to fit your drake, look on battleclinic.com for Drake fits.
Try to fit your ship like this.
Import it to EFT (a link is on the side) and import your character using your limited API if you haven't already.
This will tell you where the gaps in your skills are, and from there you can use EVEMon (also linked at the side) to plan your training to fill those gaps...
Hope this helps any further questions let us know. But without your current fit it's hard to see where your going wrong.
Brief run down of module types...
the invulnerability field, this increases your resistance to damage accross the board.
Hardners, these produce a higher resistance but only to one of the four damage types
Booster, these recharge a chunk of your shield in exchange for capacitor useage.
Extenders, these increase your shield capacity at the expense of your signiture making it easier to hit you.
Rechargers, these increase the speed of your shield recharge, but weaken your total shield capacity.
Hardners, boosters and the invulnerability field are active modules which penalise you by using Capacitor charge, the others are Passive which penalise you in different ways.