choosing workshops/conferences to attend and publish research
What one gets from attending conferences depends a lot on some personal factors, especially for junior researchers: some people socialize easily and can build fruitful professional relationships, some people are well organized and able to continue their regular work on their laptop while attending talks, some people are interested in almost every talk whether it's close to their research area or not, etc.

Personally I'm not very good at any of these things :) This is why I don't try to maximize the conferences I attend. I try to attend a couple every year, most of the time when I present something. So I choose conferences primarily as a venue for the topic/level of my paper.

To me conferences are a good way to get a general overview of what the field has been up to, finding what are the interesting new directions and the odd clever approach. Poster session are usually a good way to discuss things in more detail and ask about things which are a bit far from my own research area. I often find many interesting things to study later at conferences... and usually I don't have enough time to actually study them later ;) But overall it's really useful in order to see where my work stands in the context of the community.