I want to write a sentence to a friend indicating that instead of looking at the one thing, it's better to look at something else. Do I say, "I'd rather" or I'll rather" look?
I would rather / I'd rather
This is an example of the subjunctive -- something that refers to possibilities rather than facts.
Since you are giving your friend advice on what to do, it may or may not be done:
I would rather look at something else (if I were you).
Anytime the situation is theoretical, or not certain, you should use the subjunctive ("I would rather").
Don't forget to capitalize "I".
I will rather / I'll rather
We discussed in the comments whether "I will rather" ("I'll rather") also exists. Google N-grams confirms that "I will rather" has almost disappeared, but it was more common before 1900.
Here are a couple of ways that "I will rather" may make sense:
- When I die, I will rather be cremated than buried.
- When I go to Italy next year, I will rather visit my birthplace than my uncle.
- When I go to Greece next year, I will rather go to the islands than the mainland.
In each of these cases, the speaker is certain, and it is not theoretical.
The first one -- death -- is especially certain. It may not make sense to say:
- If I eventually die, I would rather be cremated than buried.
Feel free to use "I will rather" if you have a situation where you are certain of the future.