An error I’ve seen a lot of Spanish learners make is when they want to say “a lot of…”. There are an endless number of examples you could use, and I’ll look at three here:
There was a lot of traffic yesterday morning when I was going to work
A lot of people think that they should go on holiday together
We spend a lot of money when we go shopping
When people see the phrase “a lot of…”, they are often tempted to translate it into Spanish as
Mucho de
This is an understandable mistake, as in English we have the preposition “of” in the phrase. Also, many English natives are likely to have studied French at some point, and the phrase in French is “beaucoup de”. But in Spanish the phrase above is unfortunately not correct.

A good way of learning how to translate this phrase correctly is by doing this: whenever you see the phrase “a lot of”, before translating it into Spanish first change it to either “much” or “many”. These are direct synonyms of the phrase: if the thing that comes afterwards if singular, “much” is the one we should use, whereas if it is plural we need to use “many”.
Once we’ve done this it’s much easier to remember how to translate the phrase into Spanish. We simply use the words “mucho/ mucha/ muchos/ muchas”, depending on the gender and number of the noun that follows it. In the head of a Spanish learner, the words “much” and “many” are much closer to these than “a lot of”, which is why I recommend changing it first.
So applying this new knowledge to the above sentences, they will translate as:
Hubo mucho tráfico ayer por la mañana cuando iba al trabajo
Mucha gente piensa/ muchas personas piensan que deben ir de vacaciones juntos
Gastamos mucho dinero cuando vamos de compras
As you can see, there’s no need to use the pronoun ‘de’ when we’re translating this phrase into Spanish!!