How would you talk about changes that you hope will occur in the future.

For example:

Espero que el machismo disminuya en México. 
I hope that male chauvinism diminishes in Mexico.

This construction uses the following formula:

Esperar + que + present subjunctive

Another way to address possible changes is to speak about present hypothetical situations.

For example:

Me gustaría que se eliminara el racismo.
I would like for racism to be eliminated.

Me gustaría que la opinión pública cambiara.
I would like for public opinion to change.

These sentences use the following formula:

Indirect object pronoun + gustaría + que + imperfect subjunctive 

In order to speak about hypothetical situations in the present you need to know how to form the conditional tense and the imperfect subjunctive.

The imperfect subjunctive is formed by taking the third person plural of the preterite, minus -on.

hablaron hablar-
comieron comier-
vivieron vivier-

To this stem you add the following endings: -a, -as, -a, -amos, -ais, -an.

hablar- hablara, hablaras, hablara, habláramos, hablarais, hablaran
comier- comiera, comieras, comiera, comiéramos, comierais, comieran
vivier- viviera, vivieras, viviera, viviéramos, vivierais, vivieran 

The conditional tense is formed by adding –ía: -ías, -ía, -íamos, -íais, or –ían to the end of the infinitive form of the verb.

hablar hablaría, hablarías, hablaría, hablaríamos, hablaríais, hablarían
comer comería, comerías, comerías, comeríamos, comeríais, comerían
vivir vivir’a, vivir’as, vivir’a, vivir’amos, vivir’ais, vivir’an 

Verbs that have irregular forms in the future are also irregular in the conditional. They use the same stem in the conditional as they did in the future tense.

decir: dir-         querer: querr-
hacer: har-         saber: sabr-
poder: podr-        tener: tendr-
poner: pondr-       venir: vendr-