Addresses
For ancestors you can do this on Ancestry, but I find that FindMyPast has a much easier address search function.
Sometimes the street no longer exists. This interactive map showing old/new streets of Liverpool was a regular for me. You can put in the name of a street that’s no longer there, and it will overlay with the street that’s there now. They may exist for other towns. This one is part of the Historic Liverpool website.
Even if you don’t have Facebook, set up an account just so you can use all the amazing genealogy or social history groups. Most towns have a page dedicated to their social history, with hundreds of knowledgeable members always happy to help. People are always putting up old photographs of streets etc, so you look at the gallery, or ask. If the town you’re researching doesn’t have one - set one up! This one for Liverpool photos is amazing (you’ll need to join to see it).
For living descendants, I use 192.com. Once registered you can find the town and postcodes of people (which is sometimes enough). If you want the actual address, you pay £15.95 for 6 credits (ie 6 address views).
Start a card index. Create a new card for every street you come across and write down the ancestor who lived there and when. You’ll be amazed how many times you’ll come across a street and think “I swear I’ve seen that street before”. You’ll end up with cards that really tell a story about a street and its relationship with your family.
Travel/Mariners
The Passenger Lists in the ‘immigration and Travel’ section of Ancestry are comprehensive, but if you’re looking for merchant navy records they’re exclusively on FindMyPast (under Education and Work).
You can also find mariner/seafarer records on the Crew List Online Project. It’s a not-for-profit volunteer project, set up to assist research into the records of British merchant seafarers of the late 19th and early 20th century.
For Australia the government has digitalised all their (by boat and plane), it’s an amazing resource
Names
When searching in Ancestry, use the * to search for alternative spellings. My grandma (Edna Smith) was mis-transcribed three times in records - once as Edina, once as Edva and once her surname was Simth. Try every variation and anticipate wrong spellings.
Also when searching censuses, try and get yourself inside the heads of the people who’d filled them out. In the 1921 census my grandma was officially still Edna Smith, but she’d been ‘informally adopted’ by a couple and she was their unpaid domestic. If they’d put her real name, it would have raised financial questions. However they assigned their surname to her and called her ‘adopted daughter’ even though thtat wasn’t true. It made her part of the family so they didn’t need to pay her. It also made her very difficult to find. If I’d been more open minded about the surname I’d not have dismissed the record as quickly.
Baptism records
You can find so much more information from baptism records than birth certificates. Sometimes priests/vicars would jot things in the margin. If you can’t find it digtally (ie on Ancestry or FindMyPast) find the nearest church(es) to where the mother was living, and ring round/email to find out where their records are held. It could be that the church holds them and you can go and see the ledger, or they might take a look for you. Or they’ll be held at local archives, either the local council or the library. It’ll be well worth the hassle if you find a gem.
There are also some amazing parish record websites. I regularly used the Lancashire Online Parish Clerk Project, it might be that you’ll find one for another county.
On a personal note
Be patient! Other than some instant ‘wins’ where something’s been digitally recorded and you find it at first search, most things take time. Like military records, like waiting for BDM certificates in the post, like the whole adoption records saga. Like methodically researching records where the variables are enormous. It’s often not even possible to just pop to a local library to use their archives - sometimes you need to order an archives card (which can take a while to be authorised), book an appointment (sometimes they’re only one day a week), and pre-order any records you want to look at (which means you need to get to grips with their archive system which is sometimes complicated).