Any long time Pokemon player will know that the Nintendo games have been getting easier with experience for the whole party, even when capturing Pokemon. It ends up where the whole party is overpowered instead of just the one you use the most. With the addition of Fairy types even Dragon isn’t a challenge anymore. As a result I’ve come up with some rules to make it harder and more interesting.

• No healing items can be used against wild Pokemon, that includes status cures and revives (Items held by Pokemon are fine).
• No buying healing items (you can only use what you find).
• No visiting Pokecentres to heal (only exception is if everything in the party is down).
• Only one of each Pokemon (e.g. No doubling up on Ponyta in Sinnoh).
• You can only have one fully evolved Pokemon on your team, if it loses it gets swapped for a box Pokemon (trade or stone evolutions are fully evolved when you can’t do any more e.g. Geodude>Graveller if you can’t trade this is fully evolved). This would be hard to manage late game so you pick a full team and stick with it until party wipe where they all swap out.
• No experience farming unless against Trainers (flee as many wild encounters as possible and only stay in an area when hunting a specific Pokemon).
• Team order stays the same (Turtwig, Bidoof and Starley captured in that order remain in that order in the party until switched out. Means little type advantage in battles so you have to get clever and use TMs).
• All Pokemon must have a nickname to be used (Forgetting to name one will mean you have to return to the name change NPC before you can use it).

All these things together should make the game more challenging to beat, especially with the Elite Four. It counters the experience share as the first Pokemon gets a boost while alive but takes more damage so ends up down for longer, missing out on experience that would over level it.

I got stuck on the fighting gym for a while until my Grotle evolved and learned Earthquake. By this point all my party were around the same level as the gym Leader’s.

Don’t be too strict with this, it’s designed to make things more challenging but that should not be to the detriment of fun.