A motorcycle cover should protect the bike without becoming a loose sail or resting against dangerously hot components.
Measure the motorcycle
Measure overall length, height and width with the accessories you normally leave installed. Windscreens, saddlebags, top cases and tall mirrors can change the size you need.
Indoor versus outdoor covers
Indoor storage usually calls for dust and scratch protection. Outdoor storage adds requirements for water resistance, UV exposure, wind security and stronger fabric.
Fit matters
A cover that is too tight can stress seams and snag accessories. One that is excessively loose can flap in wind and rub painted surfaces. Use the manufacturer's dimensions rather than relying only on labels such as medium, large or cruiser.
Let the bike cool
Do not place a cover over hot exhaust or engine components unless the cover manufacturer specifically states that the material is designed for that exposure.
Long-term storage
Start with a clean, dry motorcycle. Use the cover's retention straps or secure points as designed and periodically check for moisture, wind movement and abrasion.