OK, so this is partly an exercise in stating the obvious - but it's a good place to start! Then you can browse through some of the many other more specific articles on the site for more information about these and many other aspects of road bike cycling...
Tip 1: Spend more time on your bike
Do you look forward to cycling and get out on your bike at every opportunity possible? It's fun reading magazines and chatting in internet forums about techniques and the latest equipment, but not actually very useful at improving your overall ability!
No amount of the latest equipment can help you compete against someone who just loves going out cycling, even if the weather is a bit less than perfect or there is something good on the TV...the only way to be as good is to be out there with them!
If possible, try and get out on your bike at least two or three times a week, even if it is usually for an hour or so after pttting the children to bed. A lot can be achieved with a regular hour of training.
Tip 2: Don't get over concerned about your average speed
Almost all cyclists have a bike computer to measure average speed, distance, fastest speed etc. This is very useful and interesting information, but remember that your primary goal is not usually to travel as far as possible, or to have an average speed as high as possible. Your goals are:
(a) to have fun and
(b) to increase your overall cycling ability
(c) to keep up with your cycling colleagues!
Average speed isn't a good measure of a particular day's performance for a whole load of reasons. Sometimes you will feel great and other times be a bit tired. Sometimes the wind and cold will slow you down. You will need to start each ride with a slow few miles of 'warm-up', so average speed will often be higher on a longer ride.
Tip 3: Cycle up hills
Cycling on the flat is fine, and with interval training can be an efficient way of training, but until you are happy going up hills you will never enjoy cycling. When you star out on your new bike you will find that even small hills are pretty tough, but it does get easier, and the sense of achievement from cycling up a lonh or steep hill is much greater than from cycling a long way on a flat road.
Practice is the only way to get better! See also cycling up hills.
Tip 4: Cycle intervals
As most cycling books and magazines will tell you, the best way to increase your cycling ability (performance and speed) is to cycle intervals. Broadly this means that you spend most (perhaps 80%) of your cycling time riding at a reasonably leisurely pace (please note: not too leisurely, just not too close to maximum potential), then cycling with much greater effort for the rest of the time.
This process is known as interval training.The length of each exertion varies, but one minute of very hard work followed by five minutes of recovery would be a good starting point - repeated about five times dring your outing. Remember to do a decent amount of warm up cycling first - don't just cycle straight ouf your driveway and ride like the clappers for a few minutes. See also cycle faster.
Tip 5: Spend less time on your bike
Doing all the above, including no. 1) spend more time on your bike? I know its great fun and that your enthusiasm might well make you want to cycle all the time. While you might think this is a good thing there is such a thing as overdoing it - and fatigue, lack of motivation and muscle pains are all close behind. Before you know it your bike is quietly gathering dust in the shed.
Take days off from cycling, and have cycling days where you just ride gently for the leisure and pleasure or you fill find that suddenly you completely lose the will to ride.It is much better to want to ride more, than to find that you lose the will to go out at all.