Hello Taika-san. I recently made a list of adjectives and adverbs I use often when I am learning another language. I hope you find this useful. As an practice exercise for me, I added the Japanese version.
easy かんたんな
hard (difficult) 難しい
quick, quickly, fast 早い
slow, slowly ゆっくり
same 同じ
similar 似ていろ
different 違う
tired 疲れ
busy 忙しい
fun, exciting 楽しみ
hot 熱い
cold 寒い
warm 暖かい
cool 涼しい
comfortable
incomfortable 不自由
pretty きれい
nice 優しい
beautiful 美しい
good 良い
bad 悪い
well 元気, 上手
poorly, bad at, not good at 下手
new 新しい
old 古い
If you ever want to practice these with me. Let me know. I can help you with your pronunciation via Skype.