Mark 1:35 speaks of Jesus getting up early to pray while it was still dark. In the European winter it's quite normal to get up in the morning while it's still dark, but Jesus didn't live in northern Europe. In Israel, even in the middle of winter, the sun is up by half past six: in the summer at about half past five. So getting up early to pray really did mean getting up early.
Today when we get up in the dark in the European winter it's okay. We turn on the light and work can begin even before the sun comes up. In 1st century Israel there were no electric lights. Everything was very quiet before the sun came up as nothing much could be done. Most people would have got up with the sun.
So by getting up early while it was still dark to pray Jesus was choosing a time to pray when there would be nothing else going on. It was the distraction-free time of the day.
If you're anything like me, you probably need a distraction-free time of the day for prayer. At some times of the day I can be very easily distracted by everything that needs to be done and all that's going on around me. At such times lots of little prayers might be said, yet such distraction doesn't really allow for spending time in God's presence in prayer. We still need some distraction-free time to spend in God's presence. For some people that might mean getting up early, for others it might mean praying in the middle of the night, others can escape distraction during their lunch break or at some other time during the day. It's not so much the exact time that's important, but the prayer. I heard last weekend about an assembly where different people in the prayer meeting reported waking up at the same time every night, spending an hour in prayer and then going back to sleep. As they discovered that many people in the assembly were saying this was happening, they began to discover that each one was waking up at a different time and that, in fact, there was a chain of people praying all night long. This wasn't something planned and structured, but simply something God was doing quietly and people only discovered later.
Every Christian doesn't have to pray at the same time. God has not given us a command to pray at 8:15am. It's the prayer that's important, not the clock. So find a time when you won't be distracted to spend time in God's presence in prayer.