In many states there are new equal pay laws. They hold a company liable if they ask an applicant what they are making now or try to offer a salary based on a response to what someone is earning now. The new requirement is that you ask an applicant up front what their salary expectations are and then you can let them know if the job is within that range. In CA if an applicant asks you for the salary range you must provide it. All of this is in an attempt to see that people with the same or similar jobs are paid the same.
This is a long way of saying that it may become harder and harder to negotiate wages. More companies may be setting one value (or a value within a very narrow range) and sticking to that

Usually i will accept it because the employer is just starting to hire me as they do not know me well even though i;ve gone through the interview process and provide my CV for them to have a general idea regarding my background. It is important to start to create value in the company you work in. Once your employer/superior noticed that you are more valuable than you are, you could ask for a pay rise or they might provide you one automatically as they appreaciate your value created for the company.

Accepting the first offer provided to you in a job negotiation is often conditional on conversations leading to that event. If a candidate had provided a target salary which she/he is seeking as part of a job application or had suggested through the interview process that they are seeking a target salary - and that target was met with the first offer - then a candidate should accept that offer as it would be consistent with their interview position.

Alternatively, if an offer was raised through an interview process without previous indication of salary target or related conversations - it raises the opportunity to further negotiate the offer and show a future-employer that the candidate has done their due-diligence (market research) and can command a more competitive salary as part of the negotiation.

As mentioned on an earlier post - most US states have banned the ability for employers to request salary history as part of their application process - so would expect the latter example to play out more often in this employment market.