What you're finding is generally down to the monitor using a cheap LCD panel, there's nothing you can really do to improve it unfortunately. When looking at monitors, there are a couple of main types of panels - "TN" is the cheapest type and is likely what you have, they can sometimes have decent viewing angles but other times they can be really poor which is what you're experiencing. The other type is "IPS" which is more expensive but has better colour accuracy and more importantly - much better viewing angles. If viewing angles are important, you're safer looking at IPS monitors or, if you're looking at TN ones, avoid the really cheap ones and check out reviews/tests to make sure the viewing angles will be acceptable.