How can I predict whether I will be able to take on a specific enemy or group?

Solution 1:

You need to look at the dot to the left of the name - the color of that will indicate how safe it is. White is and even match, blues and greens will probably be pretty easy, orange and yellow are going to be tough, and red means "Run away!".

The TYPE of dot indicates linking behavior (a single dot is normal, three dots indicate monsters that move in crowds, skulls and crowns indicate lieutenant or rare type monsters).

The color of the name indicates how aggressive the monster is.