1. Yesterday my favourite team lost, but I think if they had concentrated more they might have drawn.
This is a standard 3rd conditional construction:
If + had + past participle | would/might/should/could + have + past participle
My sister asked me to go out for dinner, and I answered that if I'm free I'll accept the invitation.
= 1st conditional for a future possibility ---> If + present | will + infinitive
My sister asked me to go out for dinner, and I answered that if I was free I'd accept the invitation.
= 2nd conditional for a hypothetical situation, or reported speech in the past
---> If + past simple | would + infinitive
Why don't you try writing a few more sentences following these formulae to give yourself some practice?