What Tips would you give to a 1st year mechanical student?

Set your goals for what you want to achieve in 4 years. YOU set it, irrespective of what your peers want. This is the hardest step and the rest will seem pretty logical, as long as you have that goal in mind.
Talk to as many people as you can about this – seniors, pass-outs, family, peers. Basically anyone and everyone, but the final decision is up to you. Some possible aims may include placement, higher studies, starting-up, or just chilling. It’s fine if it doesn’t come to you quickly, you have a lot of time ahead of you, but thinking in this direction is the most important thing, IMO.