1. Do anything good or help others to bring up the amount the companion likes you which is displayed on your screen when you bring up inventory.
It shows approval level on each characters screen to the left down towards bottom of the Inventory screen.
2. Obtain his approval doing good deeds throughout the druid grove. It is actually very easy to gain his approval if you are playing a good aligned character.
3. Once enough approval is gained Gale will tell you his secret and ask for your help. Say you would be glad to help.
4. After this you will not get really any signs he is interested. Just make sure every time there is the sign above his head you speak to him as he will ask in random places for a magic artifact he needs. This will occur 3 times in Act 1. Then on the third time he will give scene saying the items are not helping anymore for his condition.
5. If you have been doing many things he approves of and giving him the artifacts then you are on track as your approval should be good to very good with him.
6. Before patch 1 there was the initiate romance scene called the "Weave" scene in which Gale will ask if you want to experience the weave together and this scene would occur once you had high enough approval.

Since the last Hot Fix this has been changed again back to the original way. Once you have enough approval the weave scene will trigger randomly when you go back to camp. I just romanced him last night and got the weave scene early in game now and did not have to wait until the party. So, now I will need to up date this rest of the guide because I have not reached the party yet to see what scene shows now. my assumption is the scene where he talks of locking himself in his tower will now be the scene at the party as it was on release. Once I am certain I will completely redo this guide of how I got his romance to trigger.
7. At the party I am not certain which scene we now get. I assume that its the one where he tells you of locking himself away in his tower, but when I get tot the party I will completely update the guide.
8. He will tell you to enjoy yourself at the party and that would make him happy to see you have a good time.
9. You can speak to everyone at the party but do not commit to anyone else for the night. Most companions will comment about you and Gale getting along when you talk to them. [ this I believe has now changed again and I will update the party once I reach that scene.]
10. Once party is over choose a long rest and you will get the Weave scene. Gale will be looking at a conjured image of a woman. [This I believe has changed most likely back to the way it was on release, but I will update once I reach the party.]
11. When you do get the weave scene in game and you approach Gale, I find best response "is the Is that Mystra?" or for sorcerer, the line is something like "that's Mystra the one you wizards worship."
12. He will then respond with his line of being miles away.
13. Your next dialog choice should be one like "Want to tell me why you were conjuring Mystra image" or "is there something wrong?" DO NOT CHOOSE the line You wanted to show me something because the scene will end there if you do.
14. Once you have chosen the appropriate line the scene will progress and he will talk about magic and the weave and what it feels like. He will then ask you if it is the same for you.You can reply a few ways but I always reply that sounds similar to what I experience or if sorcerer you can reply with the sorcerer line.
15. He will then invite you to share reaching into the Weave together. Obviously reply to Gale with "By all means".
16. You will now be in the weave teaching with Gale. He tells you follow his lead. This part is easy if you are a wizard or sorcerer as you can do everything he asks you easily by choosing the wizard or sorcerer responses. If you are another class you have to roll dice to move on in the scene.
17.At one point you both will be channeling the weave and he asks how it feels. Reply "Magical, even Sensual".
18. Then when prompted pick the reply that It is a good night for intimacy and hole on to the moment. Any other response I think ends the scene.
19. Then the scene narrator tell you that all you have to do is think about what you want and Gale will know it. I always choose the line "Imagine kissing him slowly the passionately" [Not sure the exact wording but you get the point, pick most romantic option.]
20. He will be surprised and then tell you it is most pleasant and most wanted.
21. After this the weave disappears and he thanks you for sharing a night of magic.
The next morning you can approach him and ask him what he thought of what you pictured and he will reply that he was pleasantly surprised.
22 Now since Patch 1 there is another scene you need to get as well for romance.
23. I went and fought someone still in Act 1. For example, I waited to go to Ethel until after the party.
24. Once I had a fight and went to camp, Gale had a sign above him to speak to him. This is the scene that was originally at the party where he speaks about locking himself away in his tower for over a year due to his condition.
25. The first response to him I made was "Are you talking about your cat?"
26. He then explains she is Tressep not a cat and goes on to tell how she helped him find solution to his condition.
27. The next reply you should make to him is "Weren't you lonely in the tower?" or "Didn't you get lonely?" something like that. Then he will explain more.
28. He will then say that he imposed the locking himself away on himself for others safety and that he feels he left a better part of himself in his tower.
29. The best response here is " I rather like the Gale in front of me now, and I would like to see more of him."
30. He will then smile and get excited at the prospect but tell you his condition is to volatile right now but that this could be something reserved for the future.
At this point you will now be locked in to getting the next romance scene which will not happen until Act 2.
I really hope this guide helps those who got confused like I did once the changes happened to ACT 1 Gale romance after Patch 1.
If I missed anything please let me know so I can add it.
Good luck all Gale Mancers out there. As they just changed his romance again last update, I will completely update this guide once I reach certain points in the game to let you know how his romance now progresses.