Point ranges to remember

6-12

Enough to open a weak 2 bid (if you have a 6 card suit)

6+

Enough points to respond on the 1-level to partner who opened

6-9

Enough to preempt the bidding (if you have a 7+ card suit)

8-15

Enough to overcall on the 1-level an opponent who opens

10-15

Enough to overcall on the 2-level an opponent who opens

10+

Enough to respond to partner on the 2-level

13+

Enough to open the bidding

13-16

Enough to use a takeout double and pass.

15-17

Enough to open or overcall 1NT (if holding a balanced hand)

17+

Enough to make a reverse bid (i.e. bid your lower ranking suit first and then bidding your higher ranking suit) or jump in your own (preferably 6 card) suit

17+

Enought to use a takeout double and bid again.

19+

Enough points to make a jump shift to a new suit (preferably 4 card)

20-21

Enough to open 2NT on (if holding a balanced hand)

22

Enough to open 2 (strong, artificial bid)

25-27

Enough to open 3NT on (if holding a balanced hand)