How do I form the present subjunctive in Spanish?

The present subjunctive is formed by taking the stem of the verb in the first person present tense and adding new endings. For example, we take the teng from tengo (I have) as a starting point . As tener is an -er verb, it carries the endings a, as, a, amos, áis, an. Adjoining the stem with its new endings, we form: tengo - tengas - tenga - tengamos - tengáis - tengan. However, -ar verbs undergo the same process of maintaining the stem, but carry different endings for the present subjunctive: e, es, e, emos, éis, en. So hablar (to speak) becomes: hable - hables - hable - hablemos - habléis - hablen. Of course with many verbs in Spanish there are a number of irregulars in the present subjunctive that will need to be learnt separately.