Of American-English origin, the phrase to jockey for position means:
– (literally, of a jockey in horseracing): to manoeuvre in order to get one’s horse into a desired position at the beginning of a race;
– (figuratively): to manoeuvre in order to gain advantage over rivals in a competitive situation.

The earliest literal uses of the phrase to jockey for position that I have found are as follows, in chronological order:

1-: From The Races, published in the Buffalo Express (Buffalo, New York, USA) of Saturday 14^th August 1869 [Vol. 24, No. 8,054, page 4, column 2]:

Third Heat—Dimmick was “warming up” continually and the crowd became incensed at him and his jockeying for position. Mr. Thomas Best was also a little mean, shouting like a roaring bull at Brown Kitty, frightening her so that her driver could not bring her down to a trot. The patience of the judges and spectators was well nigh exhausted.

2-: From The Races, published in The Chicago Evening Mail (Chicago, Illinois, USA) of Friday 26^th July 1872 [Vol. 2, No. 291, page 1, column 2]:

La Crosse, July 25.—At the Oakwood races to-day, […] the second race was sweepstakes for an $800 purse. The horses taking part were as follows: McManus, Badger Girl, Columbia, Black Hawk and Queen of the West. There was considerable jockeying for position, but they finally got away on the fourth trial.

3-: From the Gold Hill Daily News (Gold Hill, Nevada, USA) of Wednesday 23^rd October 1872 [Vol. 19, No. 2,781, page 3, column 3]:

San Francisco, October 23—[…] The Alameda race track is in excellent condition, and if there’s no jockeying for position a good time is anticipated at the race on Saturday.

4-: From The Turf, published in The Inter Ocean (Chicago, Illinois, USA) of Saturday 25^th July 1874 [Vol. 3, No. 121, page 9, column 1]:

First Heat—There was a great and unnecessary delay in getting off, the drivers jockeying for position with intolerable persistence, but the judges allowed it. It was only on the twelfth attempt that they got away.

The earliest figurative uses of the phrase to jockey for position that I have found are as follows, in chronological order:

1-: From The Weekly Copiahan (Hazlehurst, Mississippi, USA) of Saturday 16^th April 1881 [Vol. 16, No. 35, page 3, column 2]:

Subscribe and pay in advance for the Copiahan. It is thought that the fun of the county canvass will open in earnest during court. Thus far we have only had a little jockeying for position, by aspirants and their friends.

2-: From the Black Hills Daily Pioneer (Deadwood, South Dakota, USA) of Saturday 13^th January 1883 [Vol. 6, No. 158, page 2, column 1]:

David Davis seems to cut no figure in the counsels of either party or faction at Springfield. Cullom is still on the inside, ready to hug the pole on the first quarter, while Raum, Oglesby, Farwell and others are jockeying for position. The contest promises to be the most exciting and uncertain of any senatorial struggle in the history of the state of late years, not excepting the Davis contest, where balloting was long and lively and where the great independent won the race by a scratch.

3-: From Exchange Notes, published in The Argos Reflector (Argos, Indiana, USA) of Thursday 9^th December 1886 [Vol. 6, No. 16, page 4, column 2]—reprinted from The Freeman:

We are afraid that the coming session of Congress will be a barren one, not because there is nothing to do, but because 1888 is only two years off. The numerous candidates are already jockeying for position, and nothing is likely to go through Congress which may by any possibility injure the chances of any man or party. A good deal of campaign capital may result from the session, but we don’t look for much else.

4-: From a letter to the Editor, by a person signing themself ‘X’, published in The Kansas Democrat (Topeka, Kansas, USA) of Tuesday 4^th August 1891 [Vol. 6, No. 1,642, page 2, column 3]:

No man of sense has honestly supposed that any fusion between the democrats and people’s party forces was possible throughout the state. Combinations more or less sincere may be made here and there, according to the temper of localities. Politicians here and there may jockey for position for 1892, but there will be no fusion until the people’s party suffers a reverse, and then the handful of democrats who now talk of it will not want to fuse unless they get a great deal lower down in humiliation than we think they are capable of sinking.