Once you have completed your first half marathon there are a couple of questions you might want to ask yourself, Did I enjoy it? Could I run faster? Could I have run it differently? Do I want to run a marathon?! Okay, maybe the last one is something you might not ask yourself immediately having finished a half marathon but it is definitely something you should think about further down the line.
The first thing to think about is how you are going to recover. Get some protein, eat well and make sure you don't run again before you are ready. This might be a couple of days or maybe even a couple of weeks. You might be sore walking up the stairs in which case it might not be the best idea to go out for another training run. That being said, it is always better to do something than sit around and get stiff. You don't have to go running, perhaps a swim or a cycle just to get the legs moving and flush them out from the half marathon.
Focus on running faster
If you enjoyed the race then you should focus on trying to run quicker. The faster you can run a half marathon generally means you can run a quicker marathon, and also improve your 10k performance off the strength from the half.
Think back to the race and maybe look at your 1km or mile splits if you wore a GPS watch, did you slow down towards the end? Perhaps you gradually got faster in which case this might suggest you could have set off a little quicker and been able to hold that pace through to the end.
Analyse your performance
With it being your first half marathon you are still learning the event and the distance. Every race you do, regardless of distance, is a learning experience and you'll always take something away from it whether that is a positive or negative experience. Should you have taken on more fluids? Eaten more before the race? Or even wore a lighter pair of shoes? These are all things to think about for the next time you race.
Adapt your training
If you think you slowed down too much in the last few miles then this needs to be looked at and maybe you could change your training to rectify this problem. If you went off at a steady pace which you thought you could hold to the finish and still slowed down, then you need to do more long runs in your training and more tempos around half marathon pace.
If you slowed down and really didn't enjoy the race then perhaps sticking to the shorter distances is better for you and running some 5k or 10k events might be more up your street. You really need to enjoy your running and racing if you want to improve and there are plenty of distances in the running world that you can find one that suits you.
The shorter the distance the less time you have to spend training for it (in general) - perhaps a few sprinters will disagree with me there. Maybe I should say the longer the race distance the more miles you have to run in training! You should train for an event that you know you have the time for, be sensible and work your training in around your job and pick the distance you can do yourself justice in.
Step up to the marathon
The jump between a 10k and a half marathon is quite big (more than double the distance) but the jump between a half and a full marathon is massive. Just because you can run a half marathon doesn't mean you are ready to run a marathon. That isn't to say that you can't run one, you just need to increase your mileage and do some more marathon specific work in the build up - a lot of it will depend how much time and effort you are willing to put into it.
Summer is an ideal time to train for a marathon. The days are longer and there is more daylight to get those double run days in, especially if you are working full time. If you happen to be a teacher then the summer is perfect as you'll get three-quarters of your training done for the marathon when you're not in work! You can be a full time athlete for six weeks, and reap the rewards in early autumn with a marathon.