Done it 4 times, including for the girlfriends daughter. It's not hard. Success rates are published by the Government and it's about 95% that are successful. Don't listen to all the people telling you it's impossible or hard because it isn't. You just need to get all the documents together and the evidence you provide needs to match up with what you write on the application form. You should not mention things that you can't back up with paperwork.

You can message me if you want any tips. Don't pay an agent, if you do, make sure they are registered with the government and not a backstreet chancer