Simply diving right into a paper trading account has a lot of value on its own, but paper trading experience is far more valuable when coupled with a robust system of analyzing your trades, both the winners and the losers.
For each trade that you make, you should know precisely why you entered and exited the trade, and what you could have done better to maximize profits and minimize risks. Successful day traders will keep a log for each trade so that they can review their notes to discover valuable patterns in their trading that provide insight into how they can do better in the future.