Two things that may also help you out:

- Watch out for gatherer's limitations. If you are damaging an item where you would have expected to have finished successfuly harvesting it, you may have been working too far into the anti-RMT territory. 150 successful gathers in one session will have you start failing. 250 will have you continuously fail.

- The special items for the leves such as "Wormless Lauan Log" or "Unknotched Mahogany Log" are treated as different items than their normal-harvesting equivilants by the game. They typically don't damage the remainder bar as quickly, but will often take two hits to harvest rather than just one, even if the normal version of the item can be harvested in one hit.