Don't add code cruft. Avoid parentheses around conditions in if-statements or with the return keyword. Don't add semicolons except where syntactically demanded in statements or to separate statements on the same line.
Don't use ALL_CAPS; use camelCase
Don't fight type inference. Use enumeration prefixes, self-references, and class names (with constructors) only when necessary or to clarify coding intent.
Don't use var when let is appropriate, especially for properties. The compiler better optimizes let statements for items whose values will not change during their lifetime. For example, Apple writes, "It is good practice to create immutable collections in all cases where the collection does not need to change. Doing so enables the Swift compiler to optimize the performance of the collections you create."
"JUST BECAUSE YOU'RE USING SWIFT DOESN'T MEAN YOUR QUESTION IS ABOUT SWIFT"
How To Get Answers
Ask your question and then be patient. Tell us what you want to happen, what is actually happening, and include any error messages you find:
Provide a scenario. "I am trying to do X, I do so by calling APIs W and Y, but Z happens instead. I see the following error messages:..."
Focus on the goal. Ask about what you're trying to achieve (the big story) rather than the specific technical detail that you believe is holding you back.
Don't solicit help. Don't say, "Does anyone here know about (for example) Protocol Extensions". Just ask your question.
Do your homework. Search the web before asking in-channel.
Be courteous Don't just paste Stack Overflow questions in-channel.
Remember the topic Refer questions about third party libraries to their developers.