Lets say I have to two keywords im focusing on: apple, apple juice. Now, I add a link to another site, what should the anchor text be? If I have the anchor text as apple juice, will that make the keyword "apple" lose value or will it kill 2 birds with one stone?
I would suggest that "apple juice" was better than "apple", as the level of competition for a broad keyword like "apple" would be very high. You should also try to vary the anchor text, e.g. sometimes "apple juice", other times "apple drink" or "concentrate apple juice". Search engines like to see variety. Make good use of the HREF TITLE tag where you can. You anchor text could be "apple", and your title tag could be "apple juice". This is especially important for images (as well as ALT tags). Cryo.
I agree with Cryo about the anchor text. Though you won't get any seo benefit from putting keywords in title attributes, I would put something useful in there for your visitors.
start with apple juice, and if you keep on working on that keyword and do things right, you should be starting to rank for the harder one eventually.
I'd suggest that you should not try and get lots and lots of links with the same link texts and keywords all of a sudden. It is a better idea to vary the link texts and get them over a period of time to avoid any penalties.