Symptoms

This article provides some links to official/published recommendations on development and usability improvement for K2 SmartForms.
 

Diagnoses

Some information on this can be found on K2 Center of Excellence site:
http://coe.k2.com/learn/k2-smartforms-design
From this page it is possible to download two documents:
- SmartForms design considerations
- SmartForms performance tuning

Following section of K2 documentation may be relevant here:
K2 SmartForms - Extending SmartForms

https://help.k2.com/onlinehelp/K2smartforms/UserGuide/4.6.9/default.htm_Extending_K2_smartforms.html?TocPath=Extending SmartForms|_____0

Other links:

This document is quite old now, but still the one of the main published SmartForms best practices documents:
http://www.k2.com/partners/smartforms-implementation-tips-doc

"SmartForm Design" document from COE:
http://coe.k2.com/files/9063
(K2COE.LEARN.TECHNICAL GUIDANCE.K2 IMPLEMENTATION BEST PRACTICES AND REFERENCE GUIDES.SMARTFORM DESIGN)

For custom development there are a few articles in help – not all have a lot of content, but this is the officially published content out there:

For Custom Controls:
http://help.k2.com/onlinehelp/k2smartforms/DevRef/current/default.htm_Considerations_and_Best_Practices_for_Custom_Controls.htm?TocPath=Custom%20Controls|_____12

Custom Themes:
http://help.k2.com/onlinehelp/k2smartforms/DevRef/current/default.htm_Considerations_and_Best_Practices_for_Custom_Themes.htm?TocPath=Custom%20Themes%20|_____3

Custom Fonts:
http://help.k2.com/onlinehelp/k2smartforms/DevRef/current/default.htm_Considerations_and_Best_Practices_for_Custom_Fonts.htm?TocPath=Custom%20Fonts|_____3

Custom Formats:
http://help.k2.com/onlinehelp/k2smartforms/DevRef/current/default.htm_Considerations_and_Best_Practices_for_Custom_Special_Formats.htm?TocPath=Custom%20Special%20Formats|_____3

Speaking specifically about SmartForms UX design at the moment there are no formal documents as creating forms with good discoverability/efficiency/learnability (i.e. usability) depends completely on the personas of the users that will end up using the form, whether they are SmartForms or not. E.g.:

• Visually dense forms are bad for in-frequent, non-domain experts.
• Visually sparse forms are bad for frequent use by pro-users.

Designing good input-forms, questionnaires, applications and dashboards are professions of their own, so it is often implies hiring relevant professional/consultancy. In case of doing this without external help Steve Krug’s book “Don’t make me Think” can be a good starting point/introduction to UX design.
 

Resolution

See above. You may also consider engaging with K2 Professional Services for help with your SmartForms development/design projects.