Bill Clinton did several things once taking office that lowered his early approval ratings dramatically. Clinton's lowest approval rating slipped down to 37% - a low-point mark I believe he reached in early June of 1993.

The reasons for these low ratings early on were largely tied to what many deemed to be Clinton's poor handling and implementation of his domestic agenda out of the gate.

His initial attempts at implementing his early economic policies after taking office were quickly called out very effectively (largely by the Republicans of course) as being something that would raise taxes for the bulk of Americans, and that was deemed very troublesome by many of the population, as Clinton initially failed to counter those claims very efficiently or effectively.

Clinton's support of the "Brady Bill" (aka the "Brady Handgun Violence Prevention Act") early on into his presidency when it was initially introduced by Chuck Schumer in February of 1993 also hurt Clinton's numbers badly amongst 2nd Amendment advocates in the next few months.

The whole "gays in the military" and the plan for the "Don't ask, don't tell" Clinton/Democrat policy also is deemed to have hurt his polling numbers early on amongst a considerable number of the electorate (both Dems and Republicans). He also took some early flak for his health care reform ideas (championed in large part by the then First Lady Hillary Clinton), and his early plans and support for NAFTA (the North American Free Trade Agreement) brought him a lot of heat from both sides of the aisle (and from Ross Perot supporters as well).

Of course, there was also the crazy "HairGate" scandal in early May of 1993, where Bill Clinton infamously received an hour-long haircut aboard Air Force One while it was parked on the tarmac at LA International Airport, where the delay caused by him getting his haircut was said to have forced the closure of two runways at the airport for security reasons for about an hour (said to have resulted in huge delays for many passengers on other flights inbound and outbound from the airport). That did not play well in the media at all, and was made by many in the press to initially have Clinton look like an entitled ass who cared little for the average traveller, even with some press calling it "the most expensive haircut in history". It was later revealed a couple months or so later that no flights were actually affected by Clinton's desire to get a trim that day aboard Air Force One on the tarmac at LAX, but the initial damage had been done and that hurt his May (and June) 1993 polling numbers as well.

Also, VERY importantly, The Branch Davidian/Waco assault, standoff, and final siege took place during this time period, and hurt Clinton dramatically in the polls for months afterwards (this incident took place between February 28th and April 19th of 1993).

For those that do not remember, that 51-day debacle resulted in a very flawed ATF (Bureau of Alcohol, Tobacco, and Firearms) Special Response Team raid on the Branch Davidian complex on February 28th, with that initial ATF law enforcement raid being violently repelled by the Branch Davidians. Finally, the siege on the Branch Davidian compound ended on April 19th, 1993 which, as we now know, also involved US Army SFOD-D ("Special Forces Operational Detachment-Delta" - aka Delta Force) involvement. The FBI took control of the scene after the initial ATF-run Feb.28th raid failed, and while the FBI was, as domestic law enforcement, legally cleared to execute the final siege/raid, Delta Force's military involvement came thanks to a then-covert Presidential Order signed by Bill Clinton that temporarily suspended Posse Comitatus (an act designed to prevent US military forces from being used against US citizens on US soil). Clinton's selective suspension of Posse Comitatus in that Branch Davidian case allowed those US military Special Operations commandos to aid the FBI HRT on US soil to act against US civilians. That final April 19th law enforcement raid resulted in the final death toll of 76 people (including many children), and it absolutely played a role in Clinton's poll numbers plummeting as well throughout May and June, and even the months beyond.

Basically, it was a host of all those things that affected his domestic policies that served to drop Clinton's early-into-his-administration poll numbers quite low. As we know though, Clinton later rebounded quite well, and even survived the Monica Lewinsky affair and impeachment proceedings to emerge to be recognized as quite a popular President after his two terms in office were complete in 2001.