A language exchange is two people helping each other, which sounds simple and collapses for predictable reasons. Almost all of them fail the same three ways, and all three are fixable before you start.
Split the time with a timer, not goodwill
Without a hard split, the exchange drifts into whichever language is easier for both of you. That is usually English, and the other person ends up getting a free lesson. Thirty minutes each, with an alarm. Switch mid-sentence if you have to. Fairness that depends on nobody noticing rarely survives a month.
Bring something to talk about
Open-ended conversation between near-strangers dies in ten minutes. Decide the topic beforehand — a news story, a photo each, a question you both answer. Prepared topics also let you look up the vocabulary in advance, which means you spend the session speaking rather than searching.
Agree how correction works
Correcting every mistake stops the conversation; correcting nothing wastes the advantage of having a native there. Agree on a rule: note errors silently and give three at the end of each half. Ask for the three things that most made you hard to understand. That is far more useful than a list of everything that was technically wrong.
Meet regularly or not at all
An exchange that happens when both people feel like it happens twice. Put it in the calendar weekly, same time, and treat it like an appointment. Also accept that most partnerships fade after a couple of months, and that this is normal. Line up a second one rather than treating the end of the first as a failure.
Timer, topic, correction rule, fixed slot. With those four in place an exchange is the cheapest speaking practice there is; without them it is a pleasant chat in your own language.