You can start with a moderated usability test of a prototype.
There are steps which will help you to organize your first simple usability testing session.
First of all, you need to know what do you want to test. You don't need a test just for test. You need to test design assumptions, e.g. would users understand what that label means or that this section is scrollable. So, write down the list of design assumptions.
The next step is a testing script. It could be a simple word document which contains: the lists of assumptions and participants, intro (brief) and a list of tasks.
List of assumptions - done
List of participants - You need to know who is your user. This step might include creating personas and recruiting process. The question is about conducting a usability test in general, so I won't go deep. Here you need to list the names of actual participants of the upcoming testing session. You need at least from 3 to 5 participants, they will detect the 80% of the most crucial issues.
Intro - Your introduction for participants. It should be helper text for yourself to not forget anything. The key points which you should mention are that you are not testing the user and that you want to know honestly what they think: e.g. we are testing an application, not you, we want to hear exactly what you think, you can't do anything wrong here etc.
Tasks - You should prepare a list of ~7-10 real scenario tasks which will test your design assumptions. Each task might have the following structure in the document: task (what you have to do), actions (what this user need to do to accomplish this task, what you think he will do), response (how the system/prototype will respond to user's actions).
Here is an example:
6. Approve the current image
a) Click on approve_image button
- Current image is marked as approved
- Next image is unlocked
Schedule a meeting for each participant. Usually, it should take ~30 minutes per user.
It can be done solo, but it's always good to have a second person who will be taking notes. It might be one of the stakeholders, e.g. project manager.
Prepare an excel file for the results. There should be presented tasks, participants, success rate, satisfaction rate, identified issues.
An example for identified issues: task (# of task), description (description of an issue) and occurred (how many times this issue occurred in this session).
Find a quite place to run a prototype test. This could be paper prototype, static HTML web page, InvisionApp's prototype etc. Start with your introduction to explain what are you going to, that you want the participant to think out loud, that you will answer their questions in the end because you want to know how people do when they don’t have someone sitting next to them. Ask if they have any questions.
You might want to sign some kind of NDA agreement with the participants
After the introduction, show to the user initial state of the system you're going to test. You may ask first what the user think it is, on what he would click first. Then start with the tasks. Always make notes, you may also make an audio or video record of a testing session.
After testing session create a report document. List there again the participants and the tasks. Then write down the results from your excel file. You should highlight the errors which appeared most of the times or which stopped the user from accomplishing the task. Write down a list of key takeaways as well as notable quotes from users, e.g. “So it shows me ‘swipe right to done’ okay let’s swipe it (swiping in the middle of the screen)”
Then, after a brainstorm session, the output should be the recommendations for improvements to designs.
Hope this will help and good luck!