get one's foot in the door

Etymology
Probably from a practice attributed to door-to-door salesmen of placing a foot in the opening of a prospective customer's door, thereby preventing the person from closing the door until the conclusion of the sales pitch.

Verb

 * 1)  To initiate contact or a relationship; to gain access, especially to an entry-level job.

Translations

 * Danish: få foden indenfor
 * Finnish: saada jalka oven väliin
 * Polish: ustawiać się, ustawić się