What could be a single word or phrase for the one who helps people to achieve their goals?

So, there are plenty of words available to accomplish this aim, however you should use them in the proper situation. I mention some of them here (please note that some of these words have other meanings too, but I just focus on the related meaning here):

Coach: Someone who trains a person or team in a sport.
e.g.: A tennis coach.

Lecturer: Someone who gives lectures, especially in a university.
e.g.: She's a brilliant lecturer.

Instructor: Someone who teaches .
e.g.: A driving instructor.

Trainer: Someone who teaches people particular skills, especially the skills they need to do a job.
e.g.: A teacher trainer.

Governess: A woman who lived with a family and taught their children in past times.
e.g.: As a governess, Charlotte Brontë received twenty pounds a year.

Educator: (formal) Someone whose job involves teaching people, or someone who is an expert on education.
e.g.: Most educators agree that class sizes are still too big.

Mentor: An experienced person who advises and helps a less experienced person.
e.g.: Auden later became a friend an mentor.

Professor: A teacher in a college or university. In Britain, a professor is a high-ranking university teacher, especially one who is head of a department.
e.g.: She was professor of linguistics at Cambridge University.

Leader: The person who directs or controls a group, organization, country, etc.
e.g.: The leader of the local black community.

Guide: Someone whose job is to take tourists to a place and show them around.
e.g.: A tour guide.

Guru: Someone who knows a lot about a particular subject, and gives advise to other people.
e.g.: A management guru.

Counsellor/counselor: Someone whose job is to help and support people with problems.
e.g.: Are you seeing a counsellor?

Consultant: Someone whose job is to advice on a particular subject.
e.g.: A management consultant.

All the meaning and examples borrowed from the Longman dictionary.

I would say facilitator or guide.

The first word to my mind is mentor:

-- an experienced and trusted adviser.

Enabler, one who enables. Not commonly used in British English.
It can also have negative connotations, meaning someone who allows an addict to keep up his addictive habit. (ref psychcentral.com, wikipedia.com )

How about guide?

Especially if "your goal" is a literal mountain peak.