I know you are wondering after telling you about eyelash extensions, I am now talking about making babies. Well, if you must know I have a degree in pharmacy. I am a licensed pharmacist.
If you have been trying to get pregnant unsuccessfully for a year, you may need to do some tests. These tests are for male and female. Though, I am going to talk more about female testing.
The first step in diagnosing an issue relating to fertility is a comprehensive appointment with a fertility expert.  You will have to discuss your medical history and lifestyle will extensively.  It may get a bit intense. You will be talking about birth control, smoking amongst other things. Usually one of the first questions regarding female fertility is whether you are ovulating or not.
Your Fertility specialist may also recommend a blood test to provide an estimate of your ovarian reserve. A pelvic exam is also an important part of evaluating fertility, along with a pap smear. Finally, an ultrasound scan will be done to rule out any structural issues to the reproductive system.

The following tests are also commonly used in the first evaluated cycle:

Cervical mucus tests: This involves a post-coital test (PCT) which determines if the sperm can penetrate and survive in the cervical mucus. It also involves a bacterial screening.
Ultrasound tests: This is used to assess the thickness of the lining of the uterus (endometrium), to monitor follicle development and to check the condition of the uterus and ovaries. An ultrasound may be conducted two to three days later to confirm that an egg has been released.

If both the semen analysis and the above testing return normal results, there is also additional testing that your fertility specialists may recommend. These tests include any of the following:

Hysterosalpingogram (HSG): This is an x-ray of your uterus and fallopian tubes.
This is a procedure that may be used if the HSG indicates the possible presence of abnormalities. The hysteroscope is inserted through the cervix into the uterus, which allows your fertility specialist to see any abnormalities, growths, or scarring in the uterus.
Endometrial biopsy: This is a procedure that involves scraping a small amount of tissue from the endometrium just before menstruation. This procedure is performed to determine if the lining is thick enough for a fertilised egg to implant in and grow. It is important to confirm that you are not pregnant before this test is performed.

These tests are not mandatory, and your fertility specialists will know which tests to recommend in your situation.
I know these seem like a whole lot of medical jargon, but a girls scout is always prepared.
I wish you the best of luck and your bundle of joy in the New Year.