This is actually a very common behavior, but one that can be pretty easily overcome with the right approach, so don't be too hard on yourself. When you're at the post-planning stage and 'stuck', the key is to break the next steps into incredibly small 'micro steps'. Those micro steps should be mapped out from a psychological perspective (not a physical perspective). This will probably be more clear from the following example:

The next step on your list is, as you said, to "get some clients on the phone".

You should break it into these micro steps:

1) Bring up your idea to whoever you'd feel most comfortable mentioning it to (e.g. maybe your best friend, or a stranger at a Meetup). They'll say something in response.

2) Listen to their response, and regardless of what they say, translate it into constructive criticism. For instance, in the worst case scenario, they may say, "that idea is the dumbest thing I've ever heard, who needs that". Translate that into, "My target market most likely doesn't include people like my friend." If they _are_ interested, find out the specifics of why, to better define your target market.

3) Next mention the idea to another person you'r comfortable with, and eventually mention it to everyone you feel comfortable with. Each time you mention it to a new person you'll have iterated the idea based on the responses of all the previous people. During this process you'll be fine tuning your idea (e.g. changing its features, changing its target market, etc.) and incrementing your confidence in talking about it.

4) Start talking to people you don't know so well about the newest iteration of the idea. Maybe go to Meetups on related topics, start posting questions on related sub-Reddits, and describe the idea to the extent that you're comfortable. If in converation, you'll get an idea of someone's background and interests before you decide to mention the idea to them. From this background you'll know whether you can present it to the person without any danger of them running with it without you, and you'll be testing your ability to predict if they're in the idea's target market (i.e. if they will like the idea when you describe it)

5) By this point you'll have significantly iterated and improved your idea, you'll have a pretty solid idea of who your potential customers are, and you'll have built up confidence anc comfort in describing it to people, a nd knowing what the key interest points are to different people.

6) Now build your list of potential customers, and plot them in a 2D graph with axes of X="potential income from the customer", and Y="likelihood of liking and agreeing to learn more about the product". This is more estimates than anything else, it's not really quantitative. Then pick the customer with the lowest_X and highest_Y and contact them first. This is because your first one or two contacts with potential customers (be it via email, or phone, or in person office visit) may very well still be awkward, so treat them as practice, and don't really worry about whether you make successful pitches or not. Step by step go up the list at a rate that lets you iterate the idea and the pitch and your confidence after each contact.

Note: in your contact with potential customers, it's best to do it in a step-wise manner that allows you to contact them more than once. For instance, send a well formed email first, and if you receive no response, call them up. Depending on who your customer is, you may be able to follow up with an in person visit if you never get through on the phone (for instance if it's a restaurant that may be too busy to field phone calls).

Also, this is obvious, but in your contact with potential customers, their likelihood of wanting to use your product will depend almost entirely on their ability to see the value in using your product. So before you contact them, think to yourself, "have I done all I can do to make my product's value obvious?" For instance, have as much _real_ data as possible on your product's effectiveness for each potential customer. This could include you bootstrapping your product so that you can collect data on its effectiveness for Customer X before you have even contacted Customer X. That's essentially like a free trial that they never even had to sign up for. You just 'show up at their door' with data from this 'free trial' that they never signed up for, showing them data on how it's helped them over the last week. You could for instance do this if you product is an app that directs customers to restaurants. You could add a restaurant to your app's listing and track # of clicks and check-ins to that restaurant before even going to the restaurant and asking them if they'd like to pay for continued listing on your app.

If you'd like to discuss any of this more specifically in relation to your idea(s) let me know,

best,

Lee