>>15155911
Learning forms and patterns such as GTR, stairs and sandwich is how you start. After that, practice transitioning to higher floors. If you want to play against competitively, holy counter is a must.
Though the best way to improve is watching player videos and seeing what techniques they use. It's even better if explain what they're doing.
Here's a tool JP players use to practice: http://1st.geocities.jp/mattulwan/puyo_simulator/tokopuyo.html