Best advice: Buy low, sell high
Yesterday I noticed EXCL at 700 sat on Cryptsy. I bought some and sold them today at 1,250 sat.
In the past, I dumped the NOBL I mined. The price went straight down the last weeks, so I decided to collect them and sell to a higher price. They are planning to go PoS soon, that's what moves the price. From 5 to 10 sat. recently.
There are some undervalued coins, dead coins with a new dev or any good news. Or even (mostly on fridays) coins that become target of a pump and dump group (which gives your good trading opportunities). You just have to do research. Stay with established coins as they often (not always) will keep or remain to a certain price.
DRK and LTC on Cryptsy, daily low for several days 0.007x, daily high 0.008x. Keep your eyes on the charts, check often reached price points and try to buy below and sell above those price points.
POT was ranging between 500 and 700 sat the last weeks, QTL had a range of 1,700 to 3,500 sat.
Another trading opportunity are coins with a spread that allows to make profit. If there's a difference of several satoshi between highest buy and lowest sell order, you can make profit with it.
You just need to know the market and put some efforts into proper research.