tee off

Starting a game of golf is called "teeing off".

This expression comes from the name of the tool which golfers use to raise the golf ball above the ground when they start at a new hole, which is called a "tee".

(some time) sharp

When you're making plans for a specific time, and don't want people to be late, you can use the word "sharp" after the time:

Be there at 8 o'clock sharp.

We start at 9:30 sharp. Don't be late!

Adding "sharp" to the time makes you seem strict, but not rude or unfriendly.

See you (there/then)!

After you've made plans to meet someone, you can use this phrase to end the conversation (whether in person, on the telephone, or through email or text message):

See you then!

Or:

See you there!