Ancestors from overseas: learning about immigration
It's rare that a family tree doesn't contain at least one ancestor who started their life overseas. Whether their reasons for emigrating were economic or driven by fears, difficulties in tracing your relatives back beyond a certain point can often indicate you’ve hit the immigration hurdle.
If your ancestor was keen to fit in and give their children the very best chance in their new home, you will at best find confusing name changes, and at worst not be able to uncover further information without difficulty. Since not all countries have their archives online, it's best to start with the immigration records that are held at the National Archive; these should give you a good idea of where you might start to look for a place of origin overseas. Online translation tools will be helpful to you if you need to work in a language other than English, and if you're still drawing a blank, check the emigration records as well; your ancestors may have left the country for a while rather than arriving, and that could be why you can't trace the line further back!
Find an Enthusiast
When investigating further records in a foreign country, it's worth finding a fellow genealogy enthusiast who has had dealings within that country as they will be able to give you pointers on how to find what you need in terms of birth, marriage and death records, and how to deal with the relevant bureaucracy. Many records will be available online and will save you a trip. But there's nothing that will make you feel so connected to your ancestors than standing in the church where they married, or searching for their gravestone.
19th Century – 20th Century Immigrants
Many of the immigrants during the 19th century were Jews fleeing Russia. 20th century arrivals were instrumental in rebuilding the country after the Second World War. As many kept close ties with home, you are probably already aware of cousins overseas who can help you with local information. Since both West Indian and Irish immigrants tended to come to the UK for economic reasons, it's reasonably easy to search through passenger lists for your ancestors, as few either changed or travelled under assumed names. With four million leaving Ireland for various destinations between the middle of the 19th century and the start of the First World War, it's no wonder that so many of us can claim Irish ancestry.
Naturalisation certificates can be something of a minefield, as names are likely to have been changed to fit in with their new home, but with a little imagination and detective work, you can make some educated guesses. For example, a family surname may have been adapted beyond recognition, but if you have a town, an address, and even an occupation, it's not too difficult to deduce that Josef and Magda became Joe and Mary, and gave their descendants the chances that they never would have had back home.