Here’s my bidding tips based on personal experience.
Expect your first low offer to be rejected out of hand. This is normal. You will be told the seller can't accept it, and that they are in no hurry to sell. Never increase your offer in the first phone call. Pick a walkaway figure and stick to it.
You will expect to go through 2 or 3 or more rounds of ‘that’s all we can afford, we will have to leave it at that so, that’s a pity’, until you get to your walkaway figure, so don’t leap up to it straightaway. In this climate the deal may take weeks or even months to do rather than days.
Also never run the house down with negative comments or pointing out the bad points in an effort to back up your low offer, you will only annoy the EA. The EA cannot use that sort of info to get the seller to drop the price. Agree it's a great property with great potential but that the money is the issue not the house.
So EA refuses you first offer, you need to make sure they actually put the offer to the seller, if the EA thinks you have any more to spend they will try and wring another few quid out of you before taking the offer to the seller. (And they’d be right to, it’s their job!). So if you are determined to get that particular property be prepared to leave it for a couple of weeks before going back with a slightly increased offer. If EA has not come back to you with a reduced asking after 2 weeks you could up your offer slightly if you wish.
Having rejected your first really low offer, the EA may come back with a slightly reduced asking. This is a signal they are prepared to do a deal and consider you a serious buyer, it’s just a case of can you both do the deal down to your walkaway point. Drop into the conversation the fact that you have viewed another property since seeing theirs, or that you are viewing something else this week. The EA is working for the seller but at the same time they are trying to do the deal, so they are working for both of you in some respects. Sometimes they are genuinely up against a seller that can’t accept the low offer and it may take a few weeks for the EA to work them down to a figure closer to your price.
Back up your really low offer with the guarantee that you have the deposit and mortgage approval and are not in a chain. NEVER give actual figures of how much you have to spend or how much savings you have. Also, you need to establish the situation of the seller – have they moved out, when can they move out, do they have anywhere to go, how soon could they close the deal. Asking this sort of information also shows you are serious about doing the deal.
You need to play hard to get - or rather play assertive and prepared to walk away. So don’t ring the EA back too quickly looking for answers and don’t snatch up the phone on the first ring when they call you back, let them leave you a message and get back to them later that day.
Don't get emotionally involved
One big mistake many amateur negotiators make is to become too emotionally attached to winning. Also, if they can see you're timid about the whole business, many will take advantage of that fact.
Most deals are only possible if both people feel they're getting something out of it. If the person across the table feels attacked, or doesn't like you, they probably won't back down. Keep calm, patient and friendly, even if the other person starts losing their cool. Make sure you leave any pride or ego at the door. You're much more likely to do well that way. That's why you will initially give a really low offer, so that you can up it a bit to where the seller feels you have gone as much as you can towards meeting them.
Let them believe the final decision doesn't rest with you
Once a negotiation starts, most people want to get it over with as quickly as possible. Don’t let your impatience beat you. One great way of doing this is to let them believe the person they're negotiating with isn't actually you, but some other "authority figure". Eg. Your husband or The Mrs, the Bank, whoever. Keep saying something like "Well, I'll have to talk it over with my spouse / partner /solicitor before I can come back to you". Keep the exchanges with EA really short to buy time, if you give a good gabber time they will rush you into something you may not have intended, like revealing you'd be prepared to pay a higher price. Good idea is to say you are not that keen on the house but the girlfriend/husband/my folks think it’s really great.