[LE] Keeping mod compatible

[chapaevcsv]

Im going to make a mod using kreation kit 64, however i'd like to keep my mod compatible with both Skyrim LE and SE. So what should i do, or maybe what should i avoid to keep my mod compatible?
Iknow it's possible, i've seen several examples

[Hanaisse]

Create your mod in the Skyrim LE creation kit first, test it in LE until it's done and ready to release then convert it to SE. That's done by simply loading the .esp into the Skyrim SE creation kit and re-saving it. This changes a flag in the .esp for SE compatibility. This cannot be done the other way around.