I'm still intrigued by the trading bot project by Brandson and have been looking into what other people have done, among them this for an example:
https://github.com/carlos8f/zenbot
Based on cursory glance into them, they seem to analyze market data of one currency and analyzes it to predict trends etc. However, recent drop of BTC price which dragged others down with it makes me think that perhaps a good trading bot should monitor more than one cryptocurrency since there seem to be relationship between them.
Walking fiend mentioned machine learning which I thought would require some special hardware but google seems to have a product for this where you can build TensorFlow model and train and run it on googles hardware for a price.
My own thought is that since markets are driven by people, who may not always make rational decisions, analyzing market data may not be enough. I believe in the US presidential election of 2016 they used bots to crawl through social media and news sites to find out whether there was positive or negative sentiment towards a candidate. Perhaps something like that could be of use in a trading bot.