OTTAWA -- Hundreds of federal Conservative party members gather in Vancouver on Thursday for a three-day policy convention.

It's their first meeting since the fall election that saw leader Stephen Harper leave his job after losing government to the Liberals.

Here are five things to watch for:

1) Harper's speech. The former prime minister is set to address the convention on Thursday night. It's his first public speech in Canada since he lost the election and stepped down as party leader. He's kept a low profile in Ottawa since and is expected to do the same at the convention after his brief address. It may be the last time for the party to hear from him as an MP, as he is expected to resign his seat in the Commons in the coming weeks.

2) Leadership candidates. The convention is a prime opportunity for people seeking to replace interim Conservative leader Rona Ambrose at the party's helm to make connections and for party members to get a measure of the candidates. Kellie Leitch, Maxime Bernier and Michael Chong are the only three candidates officially registered and are sure to have a high profile on and off the convention floor. But others thinking about a bid will also be making the rounds, including TV personality and businessman Kevin O'Leary.

3) Rona Ambrose. While Ambrose has appeared to squelch a drive to get her to run for the leadership, it may not be dead yet. A petition seeking to change the party's constitution to allow interim leaders to run for the permanent job continues to circulate. If there's enough support, it could be brought forward at a constitutional workshop session on Friday and, if it passed there, handed over to the general membership for a vote.

4) Party policy. There are dozens of proposed policy changes set to be debated. One that many are closely watching is a bid to drop language from the existing platform that says the party supports legislation defining marriage as a union between one man and one woman. Several riding associations are seeking to have that section deleted, arguing it's no longer necessary to have a divisive policy on the books.

5) Grassroots power. Many convention delegates are headed to Vancouver seeking to return more control over party affairs to the rank-and-file membership. Several constitutional amendments suggest a there is lot of tension over how Harper and party brass ran the show. Delegates are arguing for more transparency and oversight on how the party spends its money, elects its leadership and other issues.