Off the top of my head, you can use
1. the modal verb "will" before a verb in the infinitive without "to"
2. "am/is/are going" before a verb in the infinitive with "to"
3. the present or present continuous tense, often with a modifier to show that it will happen in the future:
1. I *will* visit my dad tomorrow. We *will* have an argument, I'm sure.
2. I *am going* to eat the entire cake once it has finished baking. I *am going* to regret it, but that *is not going* to stop me.
3. I *am taking* the kids to the lake Sunday, but first we *are having* a giant junk food breakfast.
There are others (e.g. future perfect: "I will have eaten all the cake before they arrive"). Check Chris's link for more detail.