Language is very important in validating people. Here are some tips for using validating language when someone confides in you with a problem.
1. Repeat their own words - or similar words - back to them. Focus on the adjectives they use to describe the situation and how they feel. If you friend says something was annoying, use words that mean "annoying." If your friend says something was horrible, use words that mean "horrible." Choose your words based on your friend's words, not on the objective situation.
2. "Sucks" is a great word because it is versatile. You can say, "That sucks," when something is inconvenient or when something is very upsetting. It's a great word to use when you're communicating with someone online and can't tell how much of an issue it is to them.
3. When in doubt, use stronger words. It's much easier for a friend to say, "Actually, it's not that bad," if you overestimate the severity of the issue than it is to say, "Actually, it's much worse than you think," if you underestimate.
4. When typing, do not repeat phrases in quotations. Here's an example I've seen:
You said that you have too much going on.
You said that you have "too much" going on.
The first sentence simply confirms what the person said, but the second sentence says, "You claim that you have too much going on, but you actually don't." Quotations are very invalidating. Avoid putting the other person's words into quotations, even if you think they're using words or phrases incorrectly.