Getting him to like you is easy since you can just ask him questions. When it comes to decisions, that's when things get conflicting.
Haven
Elf Inquisitor: Elves rules! Am I right? *Raises hand in anticipation of a high-five*
Solas Disapproves
Questions about Corypheus
Elf Inquisitor: Tell me more about Corypheus.
Solas: Why don't you ask Cassandra or Varric? I'm sure they know more about it than I do.
Elf Inquisitor: Oh yeah! I forgot Varric already met Corypheus. Haha, thanks Solas! (:
Solas Disapproves
Conscript Mages:
As a player who played mage in every dragon age game. While most mages are acceptable you have to consider the lowest denominator when you are managing them because they make poor decisions every time. If the mages in the circle can't handle their own members, how can I expect them to take care of themselves if freed? Also until they pick a new leader other than Fiona, I shall conscript them rather than view as equals. Because I hate Fiona.
Solas Disapproves
Winter Palace:
Elf Inquisitor: You know what would be the real talk of the town? Stabbing Florianne in front of everyone.
Solas Disapproves
Elf Inquisitor: Elves rule. And Briala has the secret password to eluvians. And Leliana did say the lower the person, the more grateful they will be for rising them up.
Solas Disapproves
Well of Sorrows
Solas: Don't let Morrigan drink from the well, she's like a glutton staring at a feast.
Elf Inquisitor: Well we can't have two gluttons drink from the well. You should drink it, Solas
Solas: No. Don't ask me again.
Elf Inquisitor: Well ok, but I'll drink it.
Later:
Solas: I told you not to drink from the well!
Elf Inquisitor: Didn't I say there were two gluttons in the room?
Etcetera, and so forth. Lots of disapproves. Lots of reloads.