What plants to grow as a beginner?

If you want details, check these things first:
1. Your USDA gardening zone map, here: www.planthardiness.ars.usda.gov also check your micro climate ( is it rains a lot? or maybe more cooler summer then other surrounding areas? etc )
2. The area where you want to plant: Full sun/partial shade/deep shade?
3. The soil; clay, sand, silt, loam, peat or chalk? This is important to see if it's boggy or dry with stones or just OK?
4. Check the plants in your surroundings; what do your neighbour plant? What type of plants that thrives on roadside, abandon places and commercial areas? or the plants/wildflowers in your area? (usually these are tough plants)
5. Notes what you like, then go the nursery and ask people there on those plant; how to care, how to plant, mature height, width and shape.
6. Decide, then plant. Green finger is a matter of knowing the right plant for the right place.

Or, the easiest way...
Ornamental grasses (like mexican feather grass) combines with perennial bulbs for seasonal colors & fragrance (lilies, daffodils, hardy gladiolus, camasia), or
Native plants in your area; wildflowers (example: ox eye daisy, scabiosa, cornflowers, etc) & native grasses for a wildlife garden.

As generally speaking, there are plants which are grouped based on the nature etc and that'll be classified into
different ones e.g. field crops, annual or perennial flowering plants, vegetables, succulents, stone crops, herbs, shrubs,trees etc. In my opinion, it is better to grow field crops such as, sweet corn, wheat, rice, ginger, millet, taro, etc on which weather they depend mainly and it is natural phenomena.
Yip

It's difficult to answer as you don't state where you live but even in cold climates Cacti are a good starter plant. I live in the North of England and put my Cacti outside in the summer and bring them inside when it gets to Autumn so that will give you some idea as to their requirements. One of the best things about Cacti is that you can choose a suitable pot, use rocks/ tree branches coloured gravel and even small model animals such as lizards etc to create a miniature landscape. Hope this helps.

'Plants' is kind of a generic statement. Flowers? Begonias. Herbs? Basil. Vegetables? Tomatoes.
All are easy.

My mother started me off with a zinnia garden. If you want vegetables, try jalapeno peppers...well...any peppers. I always liked the slim jims when I could find them. They are sorta not mild...nicely warm some times...and they are great to stuff. Green peppers ... well I found I don't get a great deal of them but the plants are easy. And the sweet ones...banana peppers are real good eating.

green pepper.

Tomatoes,peppers lettuce an radishes

Go buy some seeds on the packets it will say easy to grow average or hard...just get the easy ones...Marigolds are easy....it will also tell u when to plant and give you a few tips.

Marigolds, zinnia, daylilies, german bearded iris, wave petunias are all good and fairly easy to grow.

Tomatoes

Depends on your climate. Planting berries seems to be a great way to get something to grow. This is partially attributed to the fact they are packed with seeds, with kinds like blackberries containing a seed in every nodule. I dumped a couple of those out on the side of my house along with a cantelope I cored and everything seems to be growing plentifully without me needing to provide really any care.