For me this was a hard skill to master.

对我而言，这是一个很难掌握的技巧。

You should also explain how you are overcoming (or plan to overcome) your weakness. It is particularly useful when your weakness is a hard skill that can be easily learned.

你也应说如何克服（或者计划克服）弱点。这在弱点是一项容易学习的硬技能时特别有用。