A decent landing page conversion rate is one that was better than last week.
There are a ton of questions that people ask before they start designing and writing a landing page, but most of them are pointless. They use these questions to delay the test. To procrastinate.
Because if you launch your test, it just might fail.
But failure is the whole point, as long as you learn from it. Come up with website tests that MEAN something. Tests that will teach you something about your visitors.
If you do that, there is no failed tests… just steps towards better conversions.
And a stronger website.
Just launch your test already… try to be better then yesterday.