Watch Charleon's tutorial, it has a few outdated things but is a very good starting place.

Learn Creaking Skull Manipulation. it's not too hard with a bit of practice and saves a ton of time.

Don't bother with Baselard resets or using Baselard on Great Armor. My recommendation would be to learn the manip and not reset over it, if you do use it equip it when you suspend after flying armor (baselard is useful for blue crow hallway and some other spots), but to re-equip short sword when you go to fight Great Armor.

Do shop glitch.

For movement I would recommend at least ¤trying¤ backdash jumping. The sooner you can implement it the better.

Learn the zip backups (there's a tutorial for them in the guide section)