As responder there is sometimes a debate whether you should bid your 4 card major if it is very bad, for example you are dealt.
Do you bid your very poor spade suit or do you just bid 1NT?
Almost always bid your major, especially when you have a weak hand.
This hand actually will play excellently if partner has 4 spades. With weak hands, often the contract will be a part score - we don't need a robust suit in order to play in 2♠ for example. The second significant reason we bid our spades is because the opponents might find a heart fit and compete to 2♥ - being able to compete to 2♠ will win that auction - either declaring there or forcing the opponents to 3♥. In other words, you may not even end up playing in spades, but you still need to bid them in order to be competitive in the auction.
Known exception: Comes up extremely infrequently - With a very strong hand (lots of high card points) and a very weak suit, some people suggest to not bid the suit (to avoid getting to slam with a fragile trump suit). I recommend against it if the suit is as good as J10xx.
The most important signals
Double or bid?
Bid as high as possible!
Defending against a multi 2♦
Transfer or not?
Nv compete
How strong vulnerable?
Preempt suit quality
6322 and 7222
2♣ opening
Doubleton lead
Passive lead
When to lead active
1N with 5422
Takeout double
Negative double
Splinters
Competing partscore
Try not double
Ace Ace King
2 level overcall
Lead Trumps #1
Lead Trumps #2
7 card GOOD suit
To open or not, pre-empt or not
Let the opponents play when they are misfitting
The strongest hand
Be practical
Losing trick count bidding
Favourable vulnerability
Be a nuisance
Big trump fits
What does 3♥ show?
Mental game
6+ card suits
Use puppet stayman more
Don't push slam in competition
The unusual 2♠ bid
Intermediate jumps
Conventions
Choice of equal cards
Don't false card
Never preempt with 11 points
Is the bid forcing?
Double, Double
Double 1NT, next double
Counting Habit #1
Opener rebidding bad suits
Responder bidding bad suits
2♦ opening
Don't split honors