1. FIND YOUR PERFECT 10
You need at least ten friends to have the best chance of happiness, say researchers at Nottingham University, but it's those people with the closest friends who are most content, even if they have fewer mates than average. So cultivate quality over quantity!
2. HAVE A CHAT
Calling one of the girls when you're stressed is one of our oldest biological responses, says US researcher Dr Shelley Taylor. Women are programmed to turn to friends in times of trouble, as getting together with other women boosts production of the soothing 'cuddle' hormone oxytocin.
3. GET TOGETHER
Fabulous as networking sites are for keeping in touch, you really need to see friends in person, says psychologist Dr Will Reader of Sheffield Hallam University. 'Face-to-face contact is imperative. We need to be absolutely sure that a person is going to invest in us, and is really going to be there for us when we need them.'
4. PHONE A FRIEND
Mates who shared your teenage traumas, student hangovers and first-job fears know all your secrets - and you should treasure them for it. 'Having long-term friendships makes happiness more likely,' says Dr Richard Tunney of Nottingham University. But be warned. 'We can only keep and strengthen our friendships by actively maintaining them,' he adds. So don't let things fade - pick up the phone tonight.
5. REVEAL ALL
We tend to believe that the best way to make a new friend is to ask them lots of questions, but research shows that it's just as important to disclose information about yourself, too. 'Telling a personal story to a potential friend helps move the relationship along,' says motivational speaker Leil Lowndes, who specialises in communication skills. 'And sharing vulnerability makes you memorable and brings you closer.'
6. KEEP TALKING
Things not quite right between you? 'If something your friend has said or done bothers you, talk about it and clear it up early,' says friendships specialist Florence Isaacs. Good friends will be big enough to respond honestly.
7. STRIKE A BALANCE
If you're finding that the support in your friendship is all one-way - and it's coming from you - then you need to step back and try to put less in, says counsellor Christine Northam. 'In a good relationship, there must be reciprocity.' If your mate just can't manage to support you at all, Northam suggests stepping down your contact a bit. You can still be there for her - just not 24/7.
8. FORGET THE DEBT
'It's only natural that we're happy to lend money to a friend, but when a debt is personal, we find it very difficult to pluck up the courage to ask for it back,' says Mark Hodson of PayPal UK - which estimates that 'friendship debts' in the UK amount to a staggering £4.71 billion. Hodson recommends agreeing upfront when any money should be paid back - so you can forget about the cash and get on with your friendship.
