If you want to be a professional trader, losses are part of the business. How you deal with losses, collectively called drawdowns, differentiate the amateurs from professional behavior.
If you're down 20%, you need to do 25% to get back to even. This is important because you don't participate in the upside, ie, absolute performance, until you actually make the client money.
Your sharing in the profits are called Incentive Fees or Profit Allocations and they are benchmarked against the initial account balance, aka, the "high water mark."
Your ability is going to be measured by performance or alpha, but also how little you lose. Risk adjusted returns therefore are your goal. If you can garner market-like returns but with only a fraction of the drawdown, you'll be able to differentiate yourself from the competition.
[Remember, the riches go to the salespeople. You need to learn how to ask people for money. It won't typically show up just because you have great risk adjusted returns. You need marketing and sales to 'show and tell' your performance.]
Shorter time frame trading does NOT give you more control over your losses or drawdowns. It just means that you're likely to "die by 1,000 cuts" instead of taking a position and hold the risk over night and over the weekend. Those are good risks to take. Selling or offsetting your trades because it's the end of the day is known as "bad risk" - full of giant opportunity cost. In effect, you're leaving money on the table by not taking trades home.
In order to minimize the impact on your P&L and also on your emotional constitution, you can take a haircut on your equity when you're in a drawdown. If you get to 80% of a previous high water mark, you can trade based upon 60% of your remaining equity, and effectively trade 48% of your original capital. This helps you trade smaller when your system is not aligned with what the market is doing. Your bet sizes will be based upon a smaller capital base.
Set a max drawdown limit for the day, week, and month to keep your losses in order. Examples can be "never lose more than 1.00% of your overall equity in one day," or "stop trading at -9.50% for the month" thereby avoiding a double-digit down month.
This infers that if you're at -9.50% on the 20th of the month, you stop trading until the start of the next calendar month. This may seem counter-emotional to you when I've told you to stick to your system, but you can benefit greatly as a professional trader/PM if you can say that "you've never had a down month of 10% or more." This rule is a circuit breaker in your system.
Talk to prospective clients about how they deal with losses. If you show them that you have a superior methodology for dealing with losses than the other managers they're dealing with, there is an opportunity for you to capture those assets under management.