Hindi is a language spoken in northern and central parts of India and there are well over half a billion total speakers of Hindi around the world. This places it at number three on the list of world languages which is surprising given it is only spoken in India and Fiji.
Hindi is not written using the Latin set of characters like English but is instead transcribed in Devangari. One small consolation is that it is written from left to right in the same way as English. This, it would seem, is the end of the consolations as far as the alphabet is concerned as the script features 10 vowels and 40 consonants. Hindi words are pronounced in exactly the way they are written unlike in English where words are on occasion written and pronounced in odd ways.
The stress pattern of Hindi can cause a few problems from time to time and you must remember to fully stress small words such as at and to which would not otherwise be said emphatically in typical English speech. You must also avoid being hesitant with the first part of words such as tomorrow as we do in English as these are normally pronounced fully in Hindi.
Tenses don't tend to overlap very well between English and Hindi and so many learners can find themselves using the wrong tense to express an action done in the present or past in particular. This isn't necessarily an issue but it can make your language inaccurate and frustrate native speakers. It is only ever a problem in either an exam or situation where precision of communication is important. Nonetheless, you must think about the action, when it happened and then which tense you need to use. Revise the tenses and their usage regularly and you can avoid this problem.
Articles are also a big issue in that Hindi doesn't have a definite article. This may confuse some people at first and you may find yourself looking for a word you simply cannot find. Also Remember that word order isn't going to be identical and sometimes a word for word translation will not communicate what you wish to say in an accurate manner. To this effect, always remember that in Hindi, an object always precedes the verb, something that English speakers aren't familiar with.
Upon encountering a word which would appear to be borrowed from English, always make sure to look it up anyway in case it isn't what you think. This can avoid a lot of embarrassment and also remember that it won't necessarily be pronounced in the same manner either.
Hindi is a difficult language in that it's grammar doesn't have too many points in common with English. With that in mind, remember to always concentrate on how you are forming your sentences and to allow your instincts to take over as soon as you get into the Hindi frame of mind. Taking this into consideration, there is no reason why you should make too many mistakes and the natives will be sure to appreciate your efforts.