〜ば〜ほど
The more… the more…machine translation
FormationVerb ば-form + same verb dictionary form + ほど; い-adjective: 〜ければ + 〜いほど; な-adjective: 〜なら + 〜なほど
〜ば〜ほど expresses "the more A, the more B": as the degree of A increases, the degree of B increases with it. The crucial point is REPEATING the same word twice: first in the ば-form, then in the dictionary form + ほど — 勉強すればするほど (the more you study…), 考えれば考えるほど (the more you think…).
How to connect by word type: verbs, 読めば読むほど; い-adjectives drop い, add ければ, then repeat: 安ければ安いほど; な-adjectives use なら…なほど: 簡単なら簡単なほど. In conversation, the leading ば part can be dropped, leaving just 〜ほど: 早いほどいい (the sooner the better).
Don't confuse this with 〜につれて: that pattern also describes two parallel changes, but it doesn't repeat the word and leans toward developments over time (寒くなるにつれて…). ば〜ほど, by contrast, stresses the degree correlation "however much one rises, the other rises just as much," and can also be used for general advice that has nothing to do with time.
Examples
日本語は勉強すればするほど、面白くなります。
The more you study Japanese, the more interesting it becomes.
駅に近ければ近いほど、家賃は高くなります。
The closer to the station, the higher the rent.
説明は簡単なら簡単なほど、わかりやすいです。
The simpler the explanation, the easier it is to understand.