Bankroll:
Amount of money that we are willing to deposit (INVESTMENT) in our bookmaker.
Remember that it should NEVER be money you need right away, because like all other investments this also requires time.
Stake planning
Define a fixed percentage of the bankroll for each selection and document every result. A controlled stake plan makes short-term variance easier to manage.
Do not increase exposure simply to recover a previous loss. The next decision must stand on its own data and price.
Review the market price
Compare the recommended line with the available odds, record the closing price and judge the process over a meaningful sample of matches.