Get a blank journal and start writing things down. Look up MML by Alvo Stockman if you need some ideas on how to record your routines.
If you are only six months in though you should really focus on learning your fundamentals and working your way through books. Get a copy of Mark Wilson's Complete Course in Magic or volume one of Tarbell. Dover do a great line of classics for cheap so you can build a basic library without spending a lot of money.
At six months in you shouldn't be too concerned about inventing new things, you will soon discover that a lot of this ideas already exist. Experiment with different areas as well. You may think that card tricks are the coolest but you might have a talent for cups & balls work, or coins, rope, mental magic etc so learn about everything so you know where to focus your attention.
Recording ideas is always smart but master the basics before you try to come up with the next killer release.