I keep an eye on coinmarketcap for new coins - before it hits cmc, it's too early.

Here's the table,

http://coinmarketcap.com/currencies/views/all/

If you see a '?' in the last column (7 day change), that's a new coin that's just been added to CMC and is worthy of further investigation. Sometimes CMC makes a mistakes and puts a '?' in the last column, so to make sure, check the chart to make sure it doesn't have much history.

I have a script set up to report new coins hitting CMC for me that meet certain parameters.

It's not a guarantee, but it generally throws up coins that are worthy of further investigation.