Portfolio sizing is the decision about how much of your total capital to put in each trade. Getting this right is the difference between surviving a bad streak and blowing up your account.
A common rule is to risk no more than 1-2% of your total account on any single trade. If you have $10,000, risk $100-200 per trade. This sounds small, but it means 50 consecutive losing trades could not wipe you out.
Equally weighting a portfolio means splitting your capital evenly across all positions. If you have 5 positions and $10,000, each gets $2,000. This is simple and prevents any single stock from dominating.
Over-concentration is when one position represents too large a percentage of your portfolio. A 50% position that loses 30% costs you 15% of your total account. A 10% position that loses 30% only costs 3%.
TuraTrade portfolio templates use equal weighting by default, splitting the starting capital evenly across all picks. This is a good starting point for beginners.