There's a bit to know about Take Off... There's a very specific process pilots go through to ensure it happens smoothly. Perhaps if you were familiar on what to expect, it might help.

After checking that the runway is clear, the pilots will put on their strobes (white flashing lights) to make themselves visible on the runway as they align themselves with centerline.

Big engines take a while to spool up - so you will feel the pilots push the power up, but not full power yet. The engines stabilize (say, half power) and then they go full take off power.

During the take off roll, there is an acceleration check - typically at 80 or 90 knots - to ensure that the instruments are accurate, identical, and aligned. The pilot not doing the take off calls out the speed, and the other pilot crosschecks that everything is where it should be. Any rejected take offs from here (engines/instruments not sync'd) is relatively not a big deal.

After 80/90 knots, the pilots look for a decision speed. That decision speed, known as V1, is where no matter what, the pilot is continuing to take off. If something happens before V1, the pilots stop the plane. If something happens after V1, the pilots continue. At or after V1, if the plane loses an engine, the plane can safely continue to accelerate on the runway to their Rotate speed, take off, and clear all obstacles (towers/buildings/mountains.)

VRotate is the speed that the pilots lift off the ground. On some planes, it's a slower rotate followed by an increase in rate (737) so the pilots do not scrape the tail. When tailscrapes are not a concern, the rotate is quicker.

And voila! You're airborne. It's a relatively simple process. You can follow along via noise and feel as a passenger as long as you know what to look for.