Most often there are a major tokens to trade from an Exchange with variety having potential to making profit usually most trader wish to buy a token but for professionals they see the opportunity in a token to buy or sell that token on perpectual monitor and that's where the advantage is. Most people don't see this. 

Perpectual trading works in a coordinating order by so proTraders would study the market trend if it has a low or high potential to make profit. In this effort they are aware of the risk that a token may short which mostly it would And we all want to make a set on positioning right prediction to towards a good approach for profit with the volatility of the market been unpredictable you have to be careful of marking your 'entry'. This is only possible when you can determine your price with certainty of the scale this is where traders make a lot of profit because they have been able to identify their entry into the market.

For a Perpectual trader it could be easy to make profit even at a long run while at the time there are sellers and buyers. Not to forget a percentage of your trade goes into Liquidity some traders are aware of the risk and settle for a buy market at this point USDT is traded on a Margin of PnL 

If you can imagine a trade you choose to sell eventually goes up you could loose your trading capital if TP/SL is not recorded properly this method in trading is mostly implemented for technical reasons to manage not loosing all of your capital in one trade.

Don't forget some trade are monitoring the chart movement with intentions to close your trade upon Liquidity so not all tokens have potential for you to make profit but for you to loose your trading capital to the system.

In other to avoid this, identifying a Major token to perform your trade is advisable. The more options of trading you see the more cautious you need be following the policy of 'DYOR'.

Traders position their entry early before mass adoption and eventually sell when the market has become favorable for them to take profit once you're able to identify the trend of a market you can decide to enter the market with hopes you'll make profit because of your study of the trend or rather avoid losing your capital to the market. 

Every token has a potential but unaware of who holds the largest portion of the asset, you may loose your capital to the system.

Maintaining a good portfolio is determined by which token you're trading at the moment with good intention to close the order when you have reached your level of satisfaction on how much profit you've made.  Always be cautious of the of the greed bar as it indicates the PnL signal.

Terminologies you need to understand in an exchange

• Buy button
• Sell button 
• Order book
• Open order
• TP/SL e.t.c

This will help you construct a good Margin on your trading experience and help you manage risk of loss in your trading experience. You can position to sell a trade at an open order and make profit or choose to buy a trade at an open order and still make profit but most importantly study the market, DYOR about the token Founders and be skeptical towards the take of profit by closing order to avoid Liquidating.