This is my first post to this forum - I use the GIS/Programing ones extensively.
For a cover letter what are ways that you can avoid repeating "I have done ....", "I have experience with ...", "I am experienced in..." etc
There are actually quite a few options, many of which come naturally when you're not forced to consciously write formally.
You can change the verb into an –ing:
or in some cases turn the verb into the subject or your sentence.
This gives it an assertive feel, as does any other form of eliminating personal pronouns. Though one should include some personal pronouns for fear one begins to sound impersonal. :)
You can also add introductory phrases or prepositional phrases to the beginnings of your sentences:
If you're currently writing the cover letter, it might be best to get all your thoughts and strengths down first before editing for repetition and word choice.
Instead of saying, "I have experience with X," consider describing what you did with X. "I created a global meteor defense system using Java and Arduino."