The question is in the title of this post. A couple of explanatory points:
Context: The organizers of a certain tournament cannot provide a big cash prize that would attract a lot of participants, so the organizers reached an agreement with the national sport federation that the winners of the tournament will get a direct right to play in a certain very prestigious championship. Now many players will participate in the first tournament in order to try to earn a seat in the prestigious championship. Thus, the organizers of the first tournament are unable to make it attractive by itself and parasitize the popularity of the prestigious championship.
My attempts: I looked in Reverso and found that the phrase "by itself" is usually translated as "сам по себе," but my problem is that I cannot choose the grammatical case:
(1) Они не могут сделать турнир притягивающим сам по себе.
(2) Они не могут сделать турнир притягивающим самим по себе.
(3) Они не могут сделать турнир притягивающим самого по себе.
All variants seem wrong and unnatural to me. The Russian grammatical cases make me very confused at times, and this is just a typical situation.
Another problem with variants (1)-(3) is that "самим/самого" seems to interfere with other words: for example, in Sentence (2) "самим" can be understood as referring to "они" rather than to "турнир."
I am curious how the native speakers would express the idea.
UPDATE: Please be careful with the precise meaning. Compare two sentences:
(4) They cannot make the tournament attractive by itself.
(5) They cannot make the tournament itself attractive.
I want to translate Sentence (4) to Russian, whilst Elena's answer seems to be rather a translation of Sentence (5). She offers this: Они не могут сделать сам турнир достаточно привлекательным.
The difference is this: Sentence (4) implies that the tournament is attractive, but the attractiveness is not related to the cash prize or anything else intrinsically related to the tournament; the tournament is rather a stepping stone for something else. Sentence (5) implies that the tournament is not attractive enough to make people come to play in it, but comes as a part of an attractive package (e.g., tournament + sightseeing tour + sauna + night party), so people come to the city for the whole package and play in the tournament in that city because they are already in that city.
I humbly hope you can give me nice translations of Sentence (4), not (5).