Figure out where everyone else is going to play
You have to be fast about this one. If you take forever to place your stuff, everyone is going to get annoyed at you. Do think about it though, everyone needs the 5 things. So three people are ahead of you and one behind; you know what the three will be looking for when they place and you can guess where the person behind you is likely to place so you can try to avoid getting blocked in, which is like the kiss of death.
Remember Brick and Wood in the beginning and Iron and Wheat later on. When I have to choose between them, I choose Iron, every time.
Block off a valuable hex
This one’s kinda mean. Let’s say there is only one good Iron (good number and center board) and someone has already placed on it. If you go opposite them, no one else can use this iron. It will make you both a target for the Robber but he’s manageable.
Watch for scarce resources
Look at the numbers, if you can tell at the beginning that Wheat is going to be hard to get, try to get on the most decent space for it or monopolize another resource so you can trade, either with your mates or the bank.
Look for “get a road” numbers
I will skip over an 8 Wood or a 6 Brick for two 4s of Brick and Wood each. It is so handy to get a road whenever a number is rolled. Same for Development cards. This is especially helpful in our games because of our house rule for 7s.
Keep your eye on the prize.
This may not be an issue for you but I tend to get caught up in whatever my idea is of what I’m going to do (e.g. save for a settlement or build a city) and not be flexible enough to change directions when the resources are calling for it.
For example, say I’m saving up for a city but the iron just isn’t getting rolled and now I’m close to losing half my hand if a seven comes up. Buy a Development card, Joy! Yes, it sets me back on my city but it could get me half way there in victory points or give me a knight with which to steal some Iron for a city and build my army at the same time.
My point is: be flexible and remember it’s about the points, not a vision of a lovely village with a road curving around the sea!