Scotland’s People (http://scotlandspeople.gov.uk/), get certificates for your Grandparents then work back from there. Speak to your relatives, quite often someone else in the family has done some research. You need a birth date/death date/marriage date to start.
Ancestry.com is ok but is quite unreliable. But you could work these both together this is what my husband did. Just remember that on Ancestry.com you are accepting everyone elses research. It’s better to go slow and steady and be sure. It just takes one error to give you completely wrong results.
It’s common to start by tracing one line – your paternal line as this is where you got your surname from. So your Dad’s dad, then their dad….. Then when you hit a brick wall try your Mum’s.
The very first step would be – keep it simple. On a (large) piece of paper, note down (starting with yourself and then your parents, grandparents, etc
Full Names, relationship;
Dates and places of; birth; christening; marriage; death;
Residences; Occupation and places of work;
There will probably be something that comes out of your initial finding that you will want to find out more about and that will lead you down a different route. Also it’s finding out things like your Grandmother’s maiden name – this can come as a bit of a suprise as it’s something quite a few of us forget to ask.