Spade Heart  Diamond Club
Orpington Bridge Club
0: The Weak NT

1. At pairs scoring (2 Match Points for each pair who held the same cards that you beat, 1MP for each pair you draw with), partners should compete vigorously:
to disrupt the opponents' auction; 
to win the part score;
to sacrifice cheaply; 
to push the opponents to an unmakeable level.
The occasional huge penalty is unimportant (one bad board) if more boards get small wins.

2. Some play other systems where opening a major promises a longer suit or a different range of NT but the most common locally is 4-card majors and a 12-14 NT. Open 1NT whenever balanced (4432, 4333 or 5332 in any order) and holding 12-14 HCP. A good 11 (usually with a fair 5-card suit) or a poor 15 (often exactly 3334 with poor intermediates) can be opened 1NT if that best helps partner visualise your hand. If you can open 1NT (being of the right shape and range) you should because: 
it gives the clearest picture to partner;
it has the best pre-emptive value;
it means you don't have to worry about a second bid.
Somewhat controversially, I suggest you bid 1NT even if your 5-card suit is a major (unless the HCP are highly concentrated in it). Think "Might I want to play this 5CM as trumps if partner has two small?" If not, bid NT happily.

3. Robson's bridge column in the TImes is well worth a read.