1. Don't paste your nsec in any client, use nostrr connect web extension or Amber.

2. Use nip5 address with your domain (don't use any nip5 provider)

3. Run your personal reley or backup your notes every month using metadata.nostr.com

4. Don't send much media, unless you have your own mediaserver, because you don't want your profile be useless after 10 years when the current mediaseservers is gone.

FYI: Nostr relays don't store, send and receive media, so they are very lightweight, they only send and receive json events (read nip-1)