Conditional troubles?

For drilling the 1st Conditional (If+present tense/will+infinitive), ask your S to write down as many things as they can think of about their dream holiday destination in ooh say 3 minutes. Don't worry, they can think of more later. You should do the same (or have something prepared). The idea is you are friends and you want to go on holiday together but you both want to go to different places. Try to get your S to convince you to go to his/her place with "If we go to Tenerife we will eat tapas" and you do the same "But if we go to Norway we will visit the Fjjords". Continue until you both run out of ideas, repeat the same ideas, summarise (all this will drill the correct grammar structure) then make a choice.

A nice little one for teaching the 2nd conditionl (If+past simple/would+infinitive) Write down about 8 sentences, cut them out, put them in a bag, pull out one and start talking about what you would do in that situation without saying the actual sentence. For example, written on the paper is "If you could fly...." so you could say things like "I would fly into the supermarket and buy a beer." Obviously make it harder, that was just a dumb example. The aim is to take turns guessing the exact sentence written on the piece of paper by saying as many things as and your S can think of. It's great for drilling the 2nd conditional structure and they don't even realise it.

3rd Conditional is a pain (If+had+past participle/would+have+past participle) Tell your students a horrible regret story orally (that time you spilt wine on your friends new jacket). When you're done, ask the to repeat it back to you. Write the senteces down together, and then ask what would have happened if you hadn't done A, which led to B, and to C etc. After the grammar structure is clear you can have fun with a Chain of Consequences. Start the Chain with 'If I hadn't come to English class today, I would have (eg. stayed at home) - If I had stayed at home, I would have (eg watched a movie)' etc etc etc. Get it? Keep going until something funny happens in the story. Write it down. Discuss all the funny things that would have happened if you hadn't come to class (this would also be a good time to introduce 'might/could have' as a replacement for 'would have')

Enjoy!