When looking for stocks to build up your daily watchlist, the obvious thing that you need is a stock screener. Many websites and software programs offer screeners. But, they aren't powerful enough to do the job. All the good ones require payment (stockstotrade for example). The screener that I use to find the best gainers each day is Finviz. Once you get to their website (finviz.com), you can go to their stock screener which includes a multitude of settings and filters for your personal requirements.

 

For the beginners out there who are struggling to find the "best" filters to put on screener (I was one of you), I recommend these adjustments (NOTE: These are the settings that I use):

Price- Under $4

Current Volume- Over 500k

Signal- Top Gainers

(You can find the signal option on top of the rest of the other settings)

 

Now that you have a list of about 20-50 stocks, you can click on change to reorganize the list to see the top percentage gainers, or the top percentage losers. Obviously, it is not practical to trade every stock that you see on your screener. To shorten the list down, only trade the stocks that are having these huge winners/losers based upon news, press release, etc. DO NOT trade stocks that are not trading on news as you do not know what is making them experience these percentage swings. I stress this especially for people with small accounts. 

Small account = <$2,000