There are three main body types to consider when evaluating one's strength or fitness goals.
The ectomorph, the endomorph and the mesomorph.
This article will be dealing primarily with the ectomorph frame, which we shall be familiar with as one that tends towards being long and slim, possesses a high metabolism, a large appetite and finds it hard to put on weight.
In the bodybuilding world many people refer to this build as the "hard gainer" however in truth it would be better to refer to the ectomorph as a "different gainer".
So, you're an ectomorph and you want a good home workout? Well a good workout will depend completely on your goals.
The first thing with any routine is to set your goals, after all without a planned destination how will you plan the route? Ectomorphs want to put on weight, and a few simple truths which can help you.
The first truth concerns calorie counting.
Namely, you should do it! The simple fact is that if you take in more calories than you spend on a regular basis your body will have more energetic potential for growth.
The first part of your routine then is diet.
This comes before supplements like whey protein too!.
Your diet needs to consist of five or more meals per day, in smaller portions and never leaving more than 2-3 hours between meals.
I am an ectomorph, and I had to get used to spending a lot more money on food.
It's inevitable if you're training hard anyway and certainly inevitable if you want to train and gain mass.
The keystones to a good ectomorph diet is a balance of good fats, complex carbohydrates and proteins.
Simple carbohydrates are good right after a workout.
Doing plenty of research on your own about what different foods are good for an ectomoprh diet.
Now we have the basics covered, what kind of workout will give an ectomorph good results? For mass the answer is the same as everyone else.
One should use large amounts of weight with a low several reps to increase muscle size.
If you wish to get stronger and more athletic (as opposed to just bigger) simply lower the weight and increase the reps.
This is a good idea if you are doing no other form of exercise.

"Action may not always bring happiness; but there is no happiness without action.
{Benjamin Disraeli}"

There are two basic kinds of lift, the isolation lift and the compound lift.
The first targets a small set of muscles, such as the bicep in a bicep curl.
The second works many muscle groups and a good example would be the weighted squat or indeed all the olympic lifts.
Compound lifting is always recommended for ectomorphs looking to build muscle, they will work all your body and especially target the large muscle groups like the gluteus maximus muscles which will cause a slightly larger hormone response by your body.