Muslim here. I'm open to being convinced. In fact, if you want to convince me, my inbox is open. I think it is possibly the most important question to decide on, so I'd appreciate honest discussion. Most online discussions are rarely civil because they're a little dishonest.
IMO, there is always going to be lack of evidence for or against. Agnosticism is logical, but I would rather just pick something and experiment with it. There's a theological/philosophical aspect of belief. But in the end, there will always be too little evidence and we have to pick something.
Theological reasoning:
1. First, it's not a problem we can solve. We're too busy living our lives, working 40 hours a day. Tech and society in the last 3000 years hasn't helped us with the problem at all. It's almost certain that someone in the past has figured it out, with all the nobles spending their time on something. It's possible some knowledge was destroyed, but for the most part, it's best to work with existing frameworks.
2. Religions are at their best as soon as they become popular. After a few generations, they become corrupted as they're an easy way to seize power. So be wary of anything that wasn't part of the original teachings.
3. I think a God is inevitable. You have all these planets out there, some billions of years older than ours. Even if a God didn't create the universe, it's likely that one life form has spawned a godlike entity, at least compared to ours.
4. I don't believe that God is infinitely omnipotent or omnipowerful. But relatively so. As in God might be able to destroy Earth in seconds, but that doesn't necessarily mean he can teleport or possess people.
5. Multiple gods are unlikely, because they'd be conflicted if ruling the same space. If there are other gods, they might be governing other planets or universes. But it doesn't matter. In the case of humans, it's likely that there is one God governing us.
6. If God doesn't care about us, then there is no purpose to this exercise. Earth would be accidental, like an old can of soup which bacteria somehow developed from, and we would be the bacteria. If God doesn't care, then there will never be enough evidence to work from and this could well be the case.
7. But the Abrahamic God really seems to care.
8. If God cared, he would at least let us know before destroying us for being infidels. Hence the Prophets - Jesus, Moses, Muhammad, etc.
9. Muhammad was also an outstanding individual, very brilliant and lucky. He's either a genius or divinely guided. Not a lot of people go from being an outcast in his 50s to building an empire that conquers Byzantine Rome and the Persians.
Practical reasoning:
1. Pascal's Wager.
2. A variation of Pascal's Wager: I can't see a situation where I'd be happier in life, as an atheist. The Buddhism approach of "life is suffering/impermanent" seems to be the logical outlook. A life as an atheist would mean living in constant existential crisis. I donate, without anyone seeing my donations, because I feel God would reward me for it. Maybe God doesn't actually care, but it makes my life pleasant to think he does. Religion acts as a placebo. Why would I want to remove a placebo if it works?
3. The Prophet Muhammad and his companions were great role models. People seem to point out his marriage life as a negative, but the other 99% of his life were great. Very honest, friendly, forgave enemies, very down to earth despite their power. If Muhammad says believe in Allah, then I'd do so.
4. I think life has to be anchored on to something. Should I take Job A or Job B? Which brings me closer to God? Is Job A more sinful? Sinful isn't just sex, drugs and murder. It can be subtle things like usury, which is profitable, and very well respected.
5. If God cares that we believe, then we should be fine asking for things. God has near unlimited resources; we could basically ask for anything without annoying him, and the act of prayer is also an act of worship because it demonstrates our faith.
6. Completely anecdotal, but Allah answers my prayers. I pray for money, I receive quite a lot of money. I pray to meet people for guidance, I get to meet people who give guidance. I pray for parking, a parking spot opens up. I pray for a banana in the desert, someone gives me a banana the next morning.