Question: Consider that the outcome of Alice's efforts are understood to be satisfactory or even excellent, by her peers and the upper hierarchy. Given that Alice recognises she can deliver even better than she did, how should Alice formally state that she aims to do better than she has achieved without risking being misunderstood to imply she has been underachieving?

Assuming Alice had expressed the following in a written statement ***"my goal is to be more efficient and to close more deals per month"***, if Bob when reading that may be unaware of Alice's performance history, how could Alice have phrased her statement better to guarantee that someone like Bob would never perceive it negatively?

Answer: 
Without substantially altering your sentence, the simplest way to convey that her current achievement is already very good, would be (in my opinion) to use 'even more' as an intensified form of 'more' as in

> 
> "my goal is to be **even more efficient** and to close more deals per month" 
> 
> 
> 

where she can clearly convey the meaning 'I know I am efficient; I aim to be 'even more efficient!'

Note: You might be tempted to use 'even more' twice in the sentence as in

> 
> 'my goal is to be **even more** efficient and to close **even more** more deals per month'
> 
> 
> 

in order to be **even more** impressive, but beware! -- repetition of intensified statements actually reduces the impact and can even be misinterpreted in many ways, therefore best avoided.
When taken without the full context, yes, it may appear that Alice is acknowledging inferior performance by saying "my goal is to be more efficient and to close more deals per month".

One way for Alice to restate this in a positive way would be

> 
> My successes come from continuously looking for ways to improve.
> 
> 
> 

Having a goal of continuous improvement is always taken as a positive attribute. Tying it to prior and ongoing successes emphasizes why she would do this.