Tips for a new day trader

Hey everyone , last week I started day trading with ethereum. In 5 days I've make approx 400$ in profit with 5K investment , wich I think is not bad , Of course i've missed the lowest to buy and highest to sell because of panic , but still I think its quite a good begining ?

Do you guys have any tips to continue growing exponentially each day ?

Today just seem hard because ive never seen such rollercoaster xD

Also with platform is the best for lowest fee ? im using kraken right now but its quite expensive

Thanks and best regards to you all

Apologize my english is not native