The best way to make something easy is to make it more interesting. There's little that's harder to do than something that is boring. If you're currently doing the same thing each week to develop your couples dancing, then you might find some of the following ideas helpful. This is especially so if you're keen to improve a bit faster, but you're not as keen on simply taking more classes, which could be due to boredom or cost.
Different types of classes
What type of class do you take now? They may be private lessons (1 on 1) or they might be group lessons. Each has their advantages and disadvantages. I do not think that one is actually cheaper than the other. You pay more for private classes, but you learn so much faster that it's about the same cost for a given increase in ability anyway. The major difference is that in privates you are dancing with someone who is experienced. This means that if you're a poor lead or a poor follow, then it will not be evident to you, and it will be hard for you to know if you need to improve it. Group classes give you an excellent chance to develop an ability that is more general, because you dance with many people, and they are social so often more fun. However, you're definitely able to get a lot of tailor feedback unless the instructor has that ability to pick small faults within a large group and quickly point them out to you. If you find a group class like this, then count yourself very lucky. I have only ever been in one. So if you've been doing nothing but groups, then try some privates. You can find people who do them at their home to keep the price down, if price is an issue. On the other hand if you're been doing nothing but privates, then try some group classes. They are a kit cheaper, they are a lot of fun and sometimes they are combined with social events.
You could argue that a workshop is a different type of class, but I think that they are quite different to warrant individual consideration. Workshops are not really dance classes. They typically focus on aspects of partner dancing such as musicality, arm styling, hip action or general movement exercise. Some of them are one offs and some of them run weekly. I have been to a weekly class that focused on movement techniques for Latin dancing. There was no time anyone involved up and the activities revolved around walking, core strengthening and the subtleties of different types of foot work. People who went to these classes, and put the effort in, always commented upon how they had a better understanding of what to do to get better and had a good time there because the activities were different from the usual dance class. I have also been to a musicality workshop at a Salsa festival in Hong Kong. When you have someone take the time to go over a collection of techniques that help you better understand and express music through dance, a whole new aspect of dance opens up to you. Keep your eyes open for these workshops in your local area. If you're not sure where to look, then ask your dance teacher; They should have an idea. Workshops are an excellent change and a good one will re-motivate you in your regular class – making it easier to improve.
Social events at other places or different styles
Do you ever go to social dance events? Some people do not. If you do, then do you always go to the same one? If so, then that can get boring. A simple change of scenery can make all the difference. However, sometimes it is just listening to a different instructor that can help you see things differently, and make improving dance interesting and fun (and then easier) again.
What might really make things better is a different style. I spoke a friend, who was a salsa dancer, into going to a blues class / social night that I had been going to for a while. The simple change in music made it much more enjoyable for him. However, simply doing a slightly different dance made aspects of salsa a lot clearer to him as well. But what was probably the biggest difference was the nature of the other dancers. The places he danced at had a lot of salsa dancers who were a bit snobbish because they felt they were so sophisticated being salsa dancers, which I find amazing because salsa is a street dance not even really recognizable by international dance organization, but the people at The blues class were nothing but easy going and cool (it is blues after all, and you can not get much cooler than that). You can imagine how such a different experience would be interesting and easily exposes you to aspects of couples dancing that will help you to improve your ability
Videos can be good to practice with, but they can also be a good reference. I would not have thought it possible until I experienced it, but you can spend a lazy weekend afternoon watching a dance lesson on DVD. I was visiting a friend who had injured her self dancing and had been spending the whole time watching DVDs of dance lessons and various partner dance events such as burn the floor. To this day, I can still remember some of the key points from a Scottish dance champion on how to move in rumba and noticing how my culture affects the way I dance after watching an international dance event. So if you want to kill some time with a few like-minded friends, then try watching some dance videos. It's easy to do and you will get a few extra points on how to dance better.
Books are a lot like videos. They make an excellent reference, and they can give you some insights into focused ways to improve your dancing as you casually flip through them. You probably do not want to get a book that only tells you what your foot placement should be for each type of dance. You have a dance teacher for that. Look for books that give you ideas on how you can easily improve your dance ability or give you more specific details on each dance. There are plenty of excellent free e-books online too so do an internet search for resources as well.