Before reporting a new issue, take a look at the FAQ, the changelog and the already opened issues.
If you are unsure, ask here:
What is your type of issue?
After following 1. and 3. you can open your issue

Catalogue requests

Catalogue requests should be created at https://github.com/tachiyomiorg/tachiyomi-extensions#readme, not here

Bugs

Include version (More > About > Version)
- If not latest, try updating, it may have already been solved
- Preview version is equal to the number of commits as seen in the main page
Include steps to reproduce (if not obvious from description)
Include screenshot (if needed)
If it could be device-dependent, try reproducing on another device (if possible)
For large logs use http://pastebin.com/ (or similar)
Don't group unrelated requests into one issue

DO: https://github.com/tachiyomiorg/tachiyomi/issues/24 https://github.com/tachiyomiorg/tachiyomi/issues/71

DON'T: https://github.com/tachiyomiorg/tachiyomi/issues/75

Feature requests

Write a detailed issue, explaining what it should do or how. Avoid writing just "like X app does"
Include screenshot (if needed)