There are a number of approaches. The two approaches I particularly like are: (1) the bookies and (2) swing state poll opinions. Right now, if the 7 to 13 swing states are evenly divided between Trump and Clinton, Clinton wins with at least 50 electoral votes above what she needs to win. The swing state method usually considers many of the states as solid democrat or solid republican based on the last 4 elections, of which 2 went to Obama and 2 went to Bush. I’ll have more on this later. The bookies still have Clinton ahead, with an approximately 75% chance of winning.
These predictions haven’t changed much in the last couple of months. Some believe the third party candidates could effect the results. On this issue, it is too early to tell.