Here’s a great example of what not to do.
First of all, this bit was left in the router from the previous evening. Wood shavings were loading the tracks. Please always remove bits and clean the table up.
Now, look at the bit.
The bottom of the bit is jammed into the collet. Many bits, including this one, have a radius in the metal, from the shaft to the bit itself. When you try to tighten a collet around this section of a bit, you can ruin the collet. Many bits (including this one) have a mark on them, a line, 1/4 to 1/2 inch down from the bit. This is where the top of the collet should be. If there is no mark, leave 1/4 inch. Do not jam bit bit all the way into the collet.