Working under the assumption that voting for President actually matters and cheating is negligible this election (unlikely), here are the things I think will have an impact on the outcome:

In Biden's favor:
1. Mass exodus from solidly blue states to swing states. NY and NJ residents have been fleeing due to coronavirus, economic downfall and dictatorial measures by their govts, to Florida and the midwest. California residents have been fleeing as well, to states like Idaho and Texas. However, it seems the majority of Californians have been fleeing due to political and economic reasons and will most likely blame liberal policies for their need to relocate. So, Californian transplants will likely make the states they moved to a tad more red, not blue.
2. Near 100% leftist bias, attacks and censorship against Trump by mainstream news, social media, big tech and banks.
3. Entrenched liberal govt employees, who have closer access to abilities that allow them to manipulate the vote. They may want to see the vote go to Biden due to their own career's viability and success, as they depend on larger govt, their public unions and (for intel groups, at least) safety from prosecution (although Trump hasn't held them to account legally so far).
4. Trump's minimalization of coronavirus and perceived missteps in his handling of it. Many people who have lost family and friends to coronavirus, or have suffered from it in some way, may hold Trump responsible for what it has done to them.

In Trump's favor:
1. Trump has very visible and vocal support almost everywhere, whereas Biden has almost none. It seems the few people that are vocally in support of Biden usually make it very clear to others that they don't even like Biden - he has support only because he's not Trump.
2. Obvious Leftist corruption. This has 3 parts: 2A: The multiple failed attempts to expose conspiracy/collusion by Trump, using fabricated evidence and highly corrupt members of intelligence communities. 2B: Clear bias, lies, exaggerations and widespread censorship by MSM, social media, big tech and banks. 2C: Exposure of the Bidens as highly corrupt, hypocritical and morally degenerate.
3. Strong economy - at least before COVID - and clear pro-America/America-first stances that previous Republican Presidents were afraid of even uttering (or were against, because they were compromised or corrupt)
4. The belief that a secretive plan is afoot by Trump and members of military intelligence, to bring down a cabal of sick, treasonous members of govt and elite classes who have been conspiring to sell out our nation, enrich themselves and carry out UN and communist objectives.
5. The Left's strong bent towards communism and their 8+ month long violence, looting and treasonous/anti-American chants and threats. Most Americans - including the majority of Democrats - are against this.

I think Trump will appear to be the winner tonight, but by crook or by hook, Biden will be declared the winner as more mail-in/absentee votes are counted. Then, due to Biden's corruption or clear mental decline, Kamala will be given the reins. During this time, violence will emerge from both sides. Some, if not all, violence from the Right will be staged (false flag) and be bad enough for Kamala to justify the disarmament of the US population. Even if Trump wins, however, I expect Kamala to be central to the destruction and division of the US and eventually lead us down the path of disarmament and loss of sovereignty to the UN.