I recently saw a general rule for subject-verb agreement. The rule is put the s with the noun when it is plural, with the verb when the noun is singular except with I.
This is a good rule for nouns that are regular in forming plurals. It also covers the countable nouns because they do not have a plural form so they will have an s on the verb.
The artist draws well with charcoal. (singular subject)
The artists draw well with charcoal. (plural subject)
The rice is ready so we can eat.
Activity is what you need.
Collective nouns (class, government, family, jury, committee, group, couple, or team) are usually singular.
The class begins at .
Government is a necessity though sometimes not desirable.
The family are teachers and government employees.
The committee feel they can not make a decision at this time.
Children play in the park until dark.
The women sing well together.
So the rule works well with nouns that form regular plurals. It also works well with most pronouns except the pronoun I mentioned above. I is singular but does not require an s on verbs.
A group of pronouns also can cause problems. These are the indefinite pronouns, which include some pronouns that can be either singular or plural depending on the noun they refer to. By that I mean that if the noun is countable, the indefinite pronoun can be plural. These include the pronouns (all, any, most, none, and some).
The milk is fresh. All is ready for drinking right now.
The artists are present. All are ready to show their work.
This group of pronouns includes some pronouns that are plural (both, several, many, others, more).
Both boys are tired.
Several girls have come to the game.
Others are absent.
Some people ride bicycles. More drive cars.
Also, there are several words that look plural but are singular (news, politics, economics, civics, measles, mumps, physics, statistics, and mathematics.)
At the Purdue OWL site, they point out that dollars causes some difficulties. When dollars follows a number, in other words, there is an amount of money, the verb is singular.
Five dollars is enough to pay for the ring.
But when dollars is used alone to refer to the money, it is plural.
Dollars are needed to buy that.
Words like trousers, scissors, tweezers, shears, pants, and shorts are plural.
In summary, a simple rule like put the s with the noun when it is plural, with the verb when the noun is singular except with I looks good, but in English (as usual) there are some exceptions to keep in mind.