Hi,
I would really value anyone's advice.Poppy is my 3 year old border terrier and she's been fairly easy to train.I have only one problem with her and that is that she's very wary of strangers and visitors to the house.She barks at people who try to make friends with her and although she has never attempted to bite anyone she can be quite intimidating.I would love to make her more friendly but I don't know how!Any advice please?It's also people we meet when we're out.

Do you let her greet your guests at the door? You shouldn't! When someone knocks, lock your dog in a room away from where your guests will settle. When they are in and seated let your dog in. Make sure none of your guests make a fuss, instead let your dog come to them. Poppy needs to know that when it comes to guests in the house you are in charge, not her. If she comes into the room barking, simply put her straight back out until the barking has stopped. Then let her back in. She will soon learn that she will only be allowed in when she is quiet.
Hope this may help

Thanks for your advice but she's actually fine now when people are coming into the house.It's just when  they're at the door,like deliveries or salespeople or when we're out. Sue

You could shut her in the kitchen before you answer the door, so that this behaviour doesn't become self-rewarding. (She barks therefore gets attention/the people go.)

I expect people approach her instead of allowing her to approach them?

One way of stopping this behaviour in the house is to have a pot of treats by the door and when they arrive throw several on the floor, whilst her head is down and her mouth is full I think you will find that she will discover it is a tad tricky to bark at the same time.

This will also have the side effect that she will associate visitors with good things rather than something to be uncomfortable about.

HTH