In order to extend your visa whilst you are in the UK, you could take one of many pathways. It important to note that the right advice can help you to remain in the UK for longer, and morevisas have much information that might be of benefit to you if you are in this position.
If you are in this position, and in Tier 1, then usually the only way to have leave to remain, is if your employer requests it. If they do, then you may be asked to take a test to prove your level of English language by either providing proof of a IELTS test score about 6 or by completing a Bachelors Degree which has been taught in the English language.
There is a points system to consider, which is exactly the same as the points system for your original visa application, however you should note that the age will differ to take note of the time lapsed between the time of the original application for a visa and this new one.
A working permit extension can be extended up to a max of 5 years. However, is extremely interesting to note that if you have resided in the UK for 5 years, you can actually apply for indefinite leave to remain or permanent residency.
You could also consider applying to study further after studying a degree at a UK university, or ask for leave to remain once you have finished your study, however you must be able to prove that you could support yourself financially and that you have successfully completed your studiers. You must note however, of you want to take advantage of this, then you absolute must apply for the extension before your current visa expires.
If you have studied in the UK to become a doctor or dentist, its possible to extend your visa in order to undertake training (which can be on the job training) However his is quite a restrictive visa and does not include the possibility of applying for permanent residency, as the UK expects you to return to your home country once a three year post graduate training programme has been completed.
If you are confused about which route is right for you, morevisas can help you to decide on the best course of action for your current position and can give you advice on what to do next.