We had two different approaches when potty training the boys.
The first one was the "wait until he is ready" approach. We decided to wait until he gave us the signs that he was ready. We were also inching toward a date certain (age 3) at which he needed to be potty trained for school.
Honestly he seemed more interested in letting me know that he wasn't going to use the potty than actually using the potty. So, as age 3 approached, I became ready and we moved forward. At 2 months prior to his 3rd birthday, we kicked potty training into high gear. He definitely was resistent. I remember one time knowing that he needed to go potty and sitting in the floor of the bathroom while he sat on the potty (resisting going) for an hour and a half. Eventually, he gave in. And boy, did I cheer.
We used the "sticker method" with Bakri. I hung a ribbon vertically in the bathroom with a sign at the top that said "Bakri goes to the Potty." Everytime Bakri used the potty, he got a sticker and I added one to the ribbon. He loved watching the stickers increase.
With our second son we tried the "teach him early" approach. We definitely didn't force it, but it was a natural fit since we were training our older child.
Our younger son was 14 months old when we started this and so he got a sign and a sticker ribbon on the wall too. I also started sitting Maddux on the potty when he was really young, because I could tell he needed to go. This made him very comfortable on the potty. By 17 months, Maddux was mostly potty-trained and by his second birthday he was completely potty trained. He really responded well to the "sticker method." But, most of all, I think for Maddux, it worked because it's all he really knew and it was presented to him at an early age.
Sitting or standing?- We chose to train the boys to sit. However, they both quickly changed to standing once they were comfortable using the potty regularly.
Pullups or no pullups at night?- at first, we put Maddux in a "protector" at night until he went several days with a dry "protector" aka pullup in the morning. I've found that calling something by a different name can sometimes make all the difference.
Most things are easier with the second child, because you have the first child as the example and you've been through it once. This was the case with potty-training for us. We're definitely going to start early with Trinity. Having just one child in diapers is awesome!