To have a harmonic Poster Collection on your Wall it is worth to consider your Style and most of all your Color. If you remember to stick to one or two colors you can't go wrong.
Pick one or two colors and find Posters that primary contains the chosen colors. This Room is bordeaux
and we have chosen Posters in sand/beige tones as a contrast to the dark Wall color.
Repete colors in the Room. Make sure that the colors are repeated in the room just like here where we have the bordeaux plaid and the pillow with both sand and bordeaux color. This will bind the total look together.
Perhaps a Theme? Consider if you want a Theme on your Wall like "Nature", "Retro" or something else. This will create a common thread. You can though without any problem combine freely as long as you stick to the chosen colors.
Emphasize with colored Quotes. The colored Quotes are good to emphasize the color you choose and gather the overall impression.
Lively, calm or classic Look. Strong colors will give a lively Poster Wall where muted colors will give a more calm Look. The more "simple" motifs you choose the more calm Look. Find the balance you perfer.
Black and white posters give a timeless and classic look that you can soften up by adding a few posters in a single color to highlight just that color in the room
Choose Frames after the decor. If you have Wood Furniture in your Room choose wood frames in similar type of Wood. Are you interested in getting a contrast Look choose Black Frames for light Walls or White Frames for dark Walls. The safe rule is to find Frames in same colors as the decor you have in the room in that way you'll get a good matching Look.
Same color of Frames. You get the most harmonious look by choosing all the frames on your Poster Wall in the same color.
Nevertheless if you are brave you can play with the color of the Frames by for example, putting turquoise and red frames on black/white posters.
Here again remember to stick to a few colors. This will require a wall in e.g. white. It will give a spicy but still well thought out look. On the picture here all Posters contains the color turquoise and Frames are in same color scale. The result is a colorful and provocative look.
All Posters by E are made to fit standard size Frames.
Adhere to lines. Make sure that every Poster are aligned with one or two of the other Posters. That way the eyes finds peace while exploring your new beautiful Poster Wall.
Make the pattern of Frames on the Floor so you are sure of the result before your hang them on the Wall. Move it around until it looks good.