You can't read everything. This is where your keywords come in. Whatever resource you are using, try to scan through it quickly keeping an eye open for your keywords. If you spot a keyword read the section it is in.
With books use keywords to look at the contents page and index.
Keep a sheet of paper and a pen next to you while you read and write in your notes any information you think relates to your question, especially if it mentions your keywords.
Remember pictures and diagrams may also give information so don't forget to make notes from these as well.
